diff --git a/server/Database.js b/server/Database.js
index 1a7c533a..3f0fdf79 100644
--- a/server/Database.js
+++ b/server/Database.js
@@ -22,6 +22,9 @@ class Database {
     this.authors = []
     this.series = []
 
+    // Cached library filter data
+    this.libraryFilterData = {}
+
     this.serverSettings = null
     this.notificationSettings = null
     this.emailSettings = null
@@ -436,6 +439,34 @@ class Database {
     if (!this.sequelize) return false
     return this.models.device.createFromOld(oldDevice)
   }
+
+  removeTagFromFilterData(tag) {
+    for (const libraryId in this.libraryFilterData) {
+      this.libraryFilterData[libraryId].tags = this.libraryFilterData[libraryId].tags.filter(t => t !== tag)
+    }
+  }
+
+  addTagToFilterData(tag) {
+    for (const libraryId in this.libraryFilterData) {
+      if (!this.libraryFilterData[libraryId].tags.includes(tag)) {
+        this.libraryFilterData[libraryId].tags.push(tag)
+      }
+    }
+  }
+
+  removeGenreFromFilterData(genre) {
+    for (const libraryId in this.libraryFilterData) {
+      this.libraryFilterData[libraryId].genres = this.libraryFilterData[libraryId].genres.filter(g => g !== genre)
+    }
+  }
+
+  addGenreToFilterData(genre) {
+    for (const libraryId in this.libraryFilterData) {
+      if (!this.libraryFilterData[libraryId].genres.includes(genre)) {
+        this.libraryFilterData[libraryId].genres.push(genre)
+      }
+    }
+  }
 }
 
 module.exports = new Database()
\ No newline at end of file
diff --git a/server/controllers/LibraryController.js b/server/controllers/LibraryController.js
index 33e822c8..11f545ce 100644
--- a/server/controllers/LibraryController.js
+++ b/server/controllers/LibraryController.js
@@ -5,12 +5,14 @@ const Logger = require('../Logger')
 const SocketAuthority = require('../SocketAuthority')
 const Library = require('../objects/Library')
 const libraryHelpers = require('../utils/libraryHelpers')
+const libraryItemsBookFilters = require('../utils/queries/libraryItemsBookFilters')
 const { sort, createNewSortInstance } = require('../libs/fastSort')
 const naturalSort = createNewSortInstance({
   comparer: new Intl.Collator(undefined, { numeric: true, sensitivity: 'base' }).compare
 })
 
 const Database = require('../Database')
+const libraryFilters = require('../utils/queries/libraryFilters')
 
 class LibraryController {
   constructor() { }
@@ -80,9 +82,11 @@ class LibraryController {
   async findOne(req, res) {
     const includeArray = (req.query.include || '').split(',')
     if (includeArray.includes('filterdata')) {
+      const filterdata = await libraryFilters.getFilterData(req.library)
+
       return res.json({
-        filterdata: libraryHelpers.getDistinctFilterDataNew(req.libraryItems),
-        issues: req.libraryItems.filter(li => li.hasIssues).length,
+        filterdata,
+        issues: filterdata.numIssues,
         numUserPlaylists: await Database.models.playlist.getNumPlaylistsForUserAndLibrary(req.user.id, req.library.id),
         library: req.library
       })
@@ -90,9 +94,15 @@ class LibraryController {
     return res.json(req.library)
   }
 
+  /**
+   * GET: /api/libraries/:id/episode-downloads
+   * Get podcast episodes in download queue
+   * @param {*} req 
+   * @param {*} res 
+   */
   async getEpisodeDownloadQueue(req, res) {
     const libraryDownloadQueueDetails = this.podcastManager.getDownloadQueueDetails(req.library.id)
-    return res.json(libraryDownloadQueueDetails)
+    res.json(libraryDownloadQueueDetails)
   }
 
   async update(req, res) {
@@ -214,8 +224,12 @@ class LibraryController {
     res.json(payload)
   }
 
-  // api/libraries/:id/items
-  // TODO: Optimize this method, items are iterated through several times but can be combined
+  /**
+   * GET: /api/libraries/:id/items
+   * TODO: Remove after implementing getLibraryItemsNew
+   * @param {*} req 
+   * @param {*} res 
+   */
   async getLibraryItems(req, res) {
     let libraryItems = req.libraryItems
 
@@ -431,7 +445,7 @@ class LibraryController {
   }
 
   /**
-   * api/libraries/:id/series
+   * GET: /api/libraries/:id/series
    * Optional query string: `?include=rssfeed` that adds `rssFeed` to series if a feed is open
    * 
    * @param {*} req 
@@ -498,7 +512,7 @@ class LibraryController {
   }
 
   /**
-   * api/libraries/:id/series/:seriesId
+   * GET: /api/libraries/:id/series/:seriesId
    *
    * Optional includes (e.g. `?include=rssfeed,progress`)
    * rssfeed: adds `rssFeed` to series object if a feed is open
@@ -513,7 +527,7 @@ class LibraryController {
     const series = Database.series.find(se => se.id === req.params.seriesId)
     if (!series) return res.sendStatus(404)
 
-    const libraryItemsInSeries = req.libraryItems.filter(li => li.media.metadata.hasSeries?.(series.id))
+    const libraryItemsInSeries = await libraryItemsBookFilters.getLibraryItemsForSeries(series, req.user)
 
     const seriesJson = series.toJSON()
     if (include.includes('progress')) {
@@ -533,7 +547,12 @@ class LibraryController {
     res.json(seriesJson)
   }
 
-  // api/libraries/:id/collections
+  /**
+   * GET: /api/libraries/:id/collections
+   * Get all collections for library
+   * @param {*} req 
+   * @param {*} res 
+   */
   async getCollectionsForLibrary(req, res) {
     const include = (req.query.include || '').split(',').map(v => v.trim().toLowerCase()).filter(v => !!v)
 
@@ -563,10 +582,15 @@ class LibraryController {
     res.json(payload)
   }
 
-  // api/libraries/:id/playlists
+  /**
+   * GET: /api/libraries/:id/playlists
+   * Get playlists for user in library
+   * @param {*} req 
+   * @param {*} res 
+   */
   async getUserPlaylistsForLibrary(req, res) {
     let playlistsForUser = await Database.models.playlist.getPlaylistsForUserAndLibrary(req.user.id, req.library.id)
-    playlistsForUser = playlistsForUser.map(p => p.toJSONExpanded(Database.libraryItems))
+    playlistsForUser = await Promise.all(playlistsForUser.map(async p => p.getOldJsonExpanded()))
 
     const payload = {
       results: [],
@@ -584,8 +608,14 @@ class LibraryController {
     res.json(payload)
   }
 
+  /**
+   * GET: /api/libraries/:id/filterdata
+   * @param {*} req 
+   * @param {*} res 
+   */
   async getLibraryFilterData(req, res) {
-    res.json(libraryHelpers.getDistinctFilterDataNew(req.libraryItems))
+    const filterData = await libraryFilters.getFilterData(req.library)
+    res.json(filterData)
   }
 
   /**
diff --git a/server/controllers/MiscController.js b/server/controllers/MiscController.js
index 4442a5ce..e796cc03 100644
--- a/server/controllers/MiscController.js
+++ b/server/controllers/MiscController.js
@@ -229,6 +229,10 @@ class MiscController {
     let tagMerged = false
     let numItemsUpdated = 0
 
+    // Update filter data
+    Database.removeTagFromFilterData(tag)
+    Database.addTagToFilterData(newTag)
+
     const libraryItemsWithTag = await libraryItemFilters.getAllLibraryItemsWithTags([tag, newTag])
     for (const libraryItem of libraryItemsWithTag) {
       let existingTags = libraryItem.media.tags
@@ -275,6 +279,9 @@ class MiscController {
     // Get all items with tag
     const libraryItemsWithTag = await libraryItemFilters.getAllLibraryItemsWithTags([tag])
 
+    // Update filterdata
+    Database.removeTagFromFilterData(tag)
+
     let numItemsUpdated = 0
     // Remove tag from items
     for (const libraryItem of libraryItemsWithTag) {
@@ -356,6 +363,10 @@ class MiscController {
     let genreMerged = false
     let numItemsUpdated = 0
 
+    // Update filter data
+    Database.removeGenreFromFilterData(genre)
+    Database.addGenreToFilterData(newGenre)
+
     const libraryItemsWithGenre = await libraryItemFilters.getAllLibraryItemsWithGenres([genre, newGenre])
     for (const libraryItem of libraryItemsWithGenre) {
       let existingGenres = libraryItem.media.genres
@@ -399,6 +410,9 @@ class MiscController {
 
     const genre = Buffer.from(decodeURIComponent(req.params.genre), 'base64').toString()
 
+    // Update filter data
+    Database.removeGenreFromFilterData(genre)
+
     // Get all items with genre
     const libraryItemsWithGenre = await libraryItemFilters.getAllLibraryItemsWithGenres([genre])
 
diff --git a/server/controllers/RSSFeedController.js b/server/controllers/RSSFeedController.js
index ad356fd5..51f818ef 100644
--- a/server/controllers/RSSFeedController.js
+++ b/server/controllers/RSSFeedController.js
@@ -1,5 +1,6 @@
 const Logger = require('../Logger')
 const Database = require('../Database')
+const libraryItemsBookFilters = require('../utils/queries/libraryItemsBookFilters')
 
 class RSSFeedController {
   constructor() { }
@@ -8,7 +9,7 @@ class RSSFeedController {
   async openRSSFeedForItem(req, res) {
     const options = req.body || {}
 
-    const item = Database.libraryItems.find(li => li.id === req.params.itemId)
+    const item = await Database.models.libraryItem.getOldById(req.params.itemId)
     if (!item) return res.sendStatus(404)
 
     // Check user can access this library item
@@ -45,7 +46,7 @@ class RSSFeedController {
   async openRSSFeedForCollection(req, res) {
     const options = req.body || {}
 
-    const collection = await Database.models.collection.getOldById(req.params.collectionId)
+    const collection = await Database.models.collection.findByPk(req.params.collectionId)
     if (!collection) return res.sendStatus(404)
 
     // Check request body options exist
@@ -60,7 +61,7 @@ class RSSFeedController {
       return res.status(400).send('Slug already in use')
     }
 
-    const collectionExpanded = collection.toJSONExpanded(Database.libraryItems)
+    const collectionExpanded = await collection.getOldJsonExpanded()
     const collectionItemsWithTracks = collectionExpanded.books.filter(li => li.media.tracks.length)
 
     // Check collection has audio tracks
@@ -95,8 +96,9 @@ class RSSFeedController {
     }
 
     const seriesJson = series.toJSON()
+
     // Get books in series that have audio tracks
-    seriesJson.books = Database.libraryItems.filter(li => li.mediaType === 'book' && li.media.metadata.hasSeries(series.id) && li.media.tracks.length)
+    seriesJson.books = (await libraryItemsBookFilters.getLibraryItemsForSeries(series)).filter(li => li.media.numTracks)
 
     // Check series has audio tracks
     if (!seriesJson.books.length) {
diff --git a/server/controllers/SeriesController.js b/server/controllers/SeriesController.js
index 041c0716..61801fcf 100644
--- a/server/controllers/SeriesController.js
+++ b/server/controllers/SeriesController.js
@@ -1,6 +1,7 @@
 const Logger = require('../Logger')
 const SocketAuthority = require('../SocketAuthority')
 const Database = require('../Database')
+const libraryItemsBookFilters = require('../utils/queries/libraryItemsBookFilters')
 
 class SeriesController {
   constructor() { }
@@ -25,7 +26,7 @@ class SeriesController {
       const libraryItemsInSeries = req.libraryItemsInSeries
       const libraryItemsFinished = libraryItemsInSeries.filter(li => {
         const mediaProgress = req.user.getMediaProgress(li.id)
-        return mediaProgress && mediaProgress.isFinished
+        return mediaProgress?.isFinished
       })
       seriesJson.progress = {
         libraryItemIds: libraryItemsInSeries.map(li => li.id),
@@ -62,18 +63,17 @@ class SeriesController {
     res.json(req.series.toJSON())
   }
 
-  middleware(req, res, next) {
+  async middleware(req, res, next) {
     const series = Database.series.find(se => se.id === req.params.id)
     if (!series) return res.sendStatus(404)
 
     /**
      * Filter out any library items not accessible to user
      */
-    const libraryItems = Database.libraryItems.filter(li => li.media.metadata.hasSeries?.(series.id))
-    const libraryItemsAccessible = libraryItems.filter(li => req.user.checkCanAccessLibraryItem(li))
-    if (libraryItems.length && !libraryItemsAccessible.length) {
-      Logger.warn(`[SeriesController] User attempted to access series "${series.id}" without access to any of the books`, req.user)
-      return res.sendStatus(403)
+    const libraryItems = await libraryItemsBookFilters.getLibraryItemsForSeries(series, req.user)
+    if (!libraryItems.length) {
+      Logger.warn(`[SeriesController] User attempted to access series "${series.id}" with no accessible books`, req.user)
+      return res.sendStatus(404)
     }
 
     if (req.method == 'DELETE' && !req.user.canDelete) {
@@ -85,7 +85,7 @@ class SeriesController {
     }
 
     req.series = series
-    req.libraryItemsInSeries = libraryItemsAccessible
+    req.libraryItemsInSeries = libraryItems
     next()
   }
 }
diff --git a/server/controllers/ToolsController.js b/server/controllers/ToolsController.js
index 6215dd43..9c28d618 100644
--- a/server/controllers/ToolsController.js
+++ b/server/controllers/ToolsController.js
@@ -99,15 +99,15 @@ class ToolsController {
     res.sendStatus(200)
   }
 
-  middleware(req, res, next) {
+  async middleware(req, res, next) {
     if (!req.user.isAdminOrUp) {
       Logger.error(`[LibraryItemController] Non-root user attempted to access tools route`, req.user)
       return res.sendStatus(403)
     }
 
     if (req.params.id) {
-      const item = Database.libraryItems.find(li => li.id === req.params.id)
-      if (!item || !item.media) return res.sendStatus(404)
+      const item = await Database.models.libraryItem.getOldById(req.params.id)
+      if (!item?.media) return res.sendStatus(404)
 
       // Check user can access this library item
       if (!req.user.checkCanAccessLibraryItem(item)) {
diff --git a/server/managers/PlaybackSessionManager.js b/server/managers/PlaybackSessionManager.js
index 98792941..06e50fdc 100644
--- a/server/managers/PlaybackSessionManager.js
+++ b/server/managers/PlaybackSessionManager.js
@@ -265,7 +265,7 @@ class PlaybackSessionManager {
   }
 
   async syncSession(user, session, syncData) {
-    const libraryItem = Database.libraryItems.find(li => li.id === session.libraryItemId)
+    const libraryItem = await Database.models.libraryItem.getOldById(session.libraryItemId)
     if (!libraryItem) {
       Logger.error(`[PlaybackSessionManager] syncSession Library Item not found "${session.libraryItemId}"`)
       return null
diff --git a/server/managers/PodcastManager.js b/server/managers/PodcastManager.js
index 9fe96793..743cb60b 100644
--- a/server/managers/PodcastManager.js
+++ b/server/managers/PodcastManager.js
@@ -150,7 +150,7 @@ class PodcastManager {
       return false
     }
 
-    const libraryItem = Database.libraryItems.find(li => li.id === this.currentDownload.libraryItem.id)
+    const libraryItem = await Database.models.libraryItem.getOldById(this.currentDownload.libraryItem.id)
     if (!libraryItem) {
       Logger.error(`[PodcastManager] Podcast Episode finished but library item was not found ${this.currentDownload.libraryItem.id}`)
       return false
diff --git a/server/managers/RssFeedManager.js b/server/managers/RssFeedManager.js
index bf440b46..835f408a 100644
--- a/server/managers/RssFeedManager.js
+++ b/server/managers/RssFeedManager.js
@@ -6,6 +6,7 @@ const Database = require('../Database')
 
 const fs = require('../libs/fsExtra')
 const Feed = require('../objects/Feed')
+const libraryItemsBookFilters = require('../utils/queries/libraryItemsBookFilters')
 
 class RssFeedManager {
   constructor() { }
@@ -18,15 +19,15 @@ class RssFeedManager {
         return false
       }
     } else if (feedObj.entityType === 'libraryItem') {
-      if (!Database.libraryItems.some(li => li.id === feedObj.entityId)) {
+      const libraryItemExists = await Database.models.libraryItem.checkExistsById(feedObj.entityId)
+      if (!libraryItemExists) {
         Logger.error(`[RssFeedManager] Removing feed "${feedObj.id}". Library item "${feedObj.entityId}" not found`)
         return false
       }
     } else if (feedObj.entityType === 'series') {
       const series = Database.series.find(s => s.id === feedObj.entityId)
-      const hasSeriesBook = series ? Database.libraryItems.some(li => li.mediaType === 'book' && li.media.metadata.hasSeries(series.id) && li.media.tracks.length) : false
-      if (!hasSeriesBook) {
-        Logger.error(`[RssFeedManager] Removing feed "${feedObj.id}". Series "${feedObj.entityId}" not found or has no audio tracks`)
+      if (!series) {
+        Logger.error(`[RssFeedManager] Removing feed "${feedObj.id}". Series "${feedObj.entityId}" not found`)
         return false
       }
     } else {
@@ -102,9 +103,9 @@ class RssFeedManager {
         await Database.updateFeed(feed)
       }
     } else if (feed.entityType === 'collection') {
-      const collection = await Database.models.collection.getOldById(feed.entityId)
+      const collection = await Database.models.collection.findByPk(feed.entityId)
       if (collection) {
-        const collectionExpanded = collection.toJSONExpanded(Database.libraryItems)
+        const collectionExpanded = await collection.getOldJsonExpanded()
 
         // Find most recently updated item in collection
         let mostRecentlyUpdatedAt = collectionExpanded.lastUpdate
@@ -125,8 +126,9 @@ class RssFeedManager {
       const series = Database.series.find(s => s.id === feed.entityId)
       if (series) {
         const seriesJson = series.toJSON()
+
         // Get books in series that have audio tracks
-        seriesJson.books = Database.libraryItems.filter(li => li.mediaType === 'book' && li.media.metadata.hasSeries(series.id) && li.media.tracks.length)
+        seriesJson.books = (await libraryItemsBookFilters.getLibraryItemsForSeries(series)).filter(li => li.media.numTracks)
 
         // Find most recently updated item in series
         let mostRecentlyUpdatedAt = seriesJson.updatedAt
diff --git a/server/models/Playlist.js b/server/models/Playlist.js
index dea94504..7e466289 100644
--- a/server/models/Playlist.js
+++ b/server/models/Playlist.js
@@ -1,8 +1,7 @@
-const { DataTypes, Model, Op } = require('sequelize')
+const { DataTypes, Model, Op, literal } = require('sequelize')
 const Logger = require('../Logger')
 
 const oldPlaylist = require('../objects/Playlist')
-const { areEquivalent } = require('../utils/index')
 
 module.exports = (sequelize) => {
   class Playlist extends Model {
@@ -101,49 +100,6 @@ module.exports = (sequelize) => {
       return this.create(playlist)
     }
 
-    static async fullUpdateFromOld(oldPlaylist, playlistMediaItems) {
-      const existingPlaylist = await this.findByPk(oldPlaylist.id, {
-        include: sequelize.models.playlistMediaItem
-      })
-      if (!existingPlaylist) return false
-
-      let hasUpdates = false
-      const playlist = this.getFromOld(oldPlaylist)
-
-      for (const pmi of playlistMediaItems) {
-        const existingPmi = existingPlaylist.playlistMediaItems.find(i => i.mediaItemId === pmi.mediaItemId)
-        if (!existingPmi) {
-          await sequelize.models.playlistMediaItem.create(pmi)
-          hasUpdates = true
-        } else if (existingPmi.order != pmi.order) {
-          await existingPmi.update({ order: pmi.order })
-          hasUpdates = true
-        }
-      }
-      for (const pmi of existingPlaylist.playlistMediaItems) {
-        // Pmi was removed
-        if (!playlistMediaItems.some(i => i.mediaItemId === pmi.mediaItemId)) {
-          await pmi.destroy()
-          hasUpdates = true
-        }
-      }
-
-      let hasPlaylistUpdates = false
-      for (const key in playlist) {
-        let existingValue = existingPlaylist[key]
-        if (existingValue instanceof Date) existingValue = existingValue.valueOf()
-
-        if (!areEquivalent(playlist[key], existingValue)) {
-          hasPlaylistUpdates = true
-        }
-      }
-      if (hasPlaylistUpdates) {
-        existingPlaylist.update(playlist)
-        hasUpdates = true
-      }
-      return hasUpdates
-    }
-
     static getFromOld(oldPlaylist) {
       return {
         id: oldPlaylist.id,
@@ -196,7 +152,7 @@ module.exports = (sequelize) => {
      * Get playlists for user and optionally for library
      * @param {string} userId 
      * @param {[string]} libraryId optional
-     * @returns {Promise<oldPlaylist[]>}
+     * @returns {Promise<Playlist[]>}
      */
     static async getPlaylistsForUserAndLibrary(userId, libraryId = null) {
       if (!userId && !libraryId) return []
@@ -225,9 +181,12 @@ module.exports = (sequelize) => {
             }
           ]
         },
-        order: [['playlistMediaItems', 'order', 'ASC']]
+        order: [
+          [literal('name COLLATE NOCASE'), 'ASC'],
+          ['playlistMediaItems', 'order', 'ASC']
+        ]
       })
-      return playlists.map(p => this.getOldPlaylist(p))
+      return playlists
     }
 
     /**
diff --git a/server/routers/ApiRouter.js b/server/routers/ApiRouter.js
index 260ea0cb..aa8c03a7 100644
--- a/server/routers/ApiRouter.js
+++ b/server/routers/ApiRouter.js
@@ -70,21 +70,21 @@ class ApiRouter {
     //
     this.router.post('/libraries', LibraryController.create.bind(this))
     this.router.get('/libraries', LibraryController.findAll.bind(this))
-    this.router.get('/libraries/:id', LibraryController.middleware.bind(this), LibraryController.findOne.bind(this))
+    this.router.get('/libraries/:id', LibraryController.middlewareNew.bind(this), LibraryController.findOne.bind(this))
     this.router.patch('/libraries/:id', LibraryController.middleware.bind(this), LibraryController.update.bind(this))
     this.router.delete('/libraries/:id', LibraryController.middleware.bind(this), LibraryController.delete.bind(this))
 
     this.router.get('/libraries/:id/items2', LibraryController.middlewareNew.bind(this), LibraryController.getLibraryItemsNew.bind(this))
     this.router.get('/libraries/:id/items', LibraryController.middleware.bind(this), LibraryController.getLibraryItems.bind(this))
-    this.router.delete('/libraries/:id/issues', LibraryController.middleware.bind(this), LibraryController.removeLibraryItemsWithIssues.bind(this))
-    this.router.get('/libraries/:id/episode-downloads', LibraryController.middleware.bind(this), LibraryController.getEpisodeDownloadQueue.bind(this))
+    this.router.delete('/libraries/:id/issues', LibraryController.middlewareNew.bind(this), LibraryController.removeLibraryItemsWithIssues.bind(this))
+    this.router.get('/libraries/:id/episode-downloads', LibraryController.middlewareNew.bind(this), LibraryController.getEpisodeDownloadQueue.bind(this))
     this.router.get('/libraries/:id/series', LibraryController.middleware.bind(this), LibraryController.getAllSeriesForLibrary.bind(this))
-    this.router.get('/libraries/:id/series/:seriesId', LibraryController.middleware.bind(this), LibraryController.getSeriesForLibrary.bind(this))
+    this.router.get('/libraries/:id/series/:seriesId', LibraryController.middlewareNew.bind(this), LibraryController.getSeriesForLibrary.bind(this))
     this.router.get('/libraries/:id/collections', LibraryController.middlewareNew.bind(this), LibraryController.getCollectionsForLibrary.bind(this))
-    this.router.get('/libraries/:id/playlists', LibraryController.middleware.bind(this), LibraryController.getUserPlaylistsForLibrary.bind(this))
+    this.router.get('/libraries/:id/playlists', LibraryController.middlewareNew.bind(this), LibraryController.getUserPlaylistsForLibrary.bind(this))
     this.router.get('/libraries/:id/personalized2', LibraryController.middlewareNew.bind(this), LibraryController.getUserPersonalizedShelves.bind(this))
     this.router.get('/libraries/:id/personalized', LibraryController.middleware.bind(this), LibraryController.getLibraryUserPersonalizedOptimal.bind(this))
-    this.router.get('/libraries/:id/filterdata', LibraryController.middleware.bind(this), LibraryController.getLibraryFilterData.bind(this))
+    this.router.get('/libraries/:id/filterdata', LibraryController.middlewareNew.bind(this), LibraryController.getLibraryFilterData.bind(this))
     this.router.get('/libraries/:id/search', LibraryController.middleware.bind(this), LibraryController.search.bind(this))
     this.router.get('/libraries/:id/stats', LibraryController.middleware.bind(this), LibraryController.stats.bind(this))
     this.router.get('/libraries/:id/authors', LibraryController.middleware.bind(this), LibraryController.getAuthors.bind(this))
@@ -447,11 +447,14 @@ class ApiRouter {
     }
 
     await Database.removeLibraryItem(libraryItem.id)
-    SocketAuthority.emitter('item_removed', libraryItem.toJSONExpanded())
+
+    SocketAuthority.emitter('item_removed', {
+      id: libraryItem.id
+    })
   }
 
   async checkRemoveEmptySeries(seriesToCheck, excludeLibraryItemId = null) {
-    if (!seriesToCheck || !seriesToCheck.length) return
+    if (!seriesToCheck?.length) return
 
     for (const series of seriesToCheck) {
       const otherLibraryItemsInSeries = Database.libraryItems.filter(li => li.id !== excludeLibraryItemId && li.isBook && li.media.metadata.hasSeries(series.id))
diff --git a/server/utils/queries/libraryFilters.js b/server/utils/queries/libraryFilters.js
index c0a93d15..492cbe76 100644
--- a/server/utils/queries/libraryFilters.js
+++ b/server/utils/queries/libraryFilters.js
@@ -1,7 +1,12 @@
 const Sequelize = require('sequelize')
+const Logger = require('../../Logger')
 const Database = require('../../Database')
 const libraryItemsBookFilters = require('./libraryItemsBookFilters')
 const libraryItemsPodcastFilters = require('./libraryItemsPodcastFilters')
+const { createNewSortInstance } = require('../../libs/fastSort')
+const naturalSort = createNewSortInstance({
+  comparer: new Intl.Collator(undefined, { numeric: true, sensitivity: 'base' }).compare
+})
 
 module.exports = {
   decode(text) {
@@ -381,5 +386,109 @@ module.exports = {
    */
   getLibraryItemsForCollection(collection) {
     return libraryItemsBookFilters.getLibraryItemsForCollection(collection)
+  },
+
+  /**
+   * Get filter data used in filter menus
+   * @param {oldLibrary} oldLibrary 
+   * @returns {Promise<object>}
+   */
+  async getFilterData(oldLibrary) {
+    const cachedFilterData = Database.libraryFilterData[oldLibrary.id]
+    if (cachedFilterData) {
+      const cacheElapsed = Date.now() - cachedFilterData.loadedAt
+      // Cache library filters for 30 mins
+      // TODO: Keep cached filter data up-to-date on updates
+      if (cacheElapsed < 1000 * 60 * 30) {
+        return cachedFilterData
+      }
+    }
+    const start = Date.now() // Temp for checking load times
+
+    const data = {
+      authors: [],
+      genres: new Set(),
+      tags: new Set(),
+      series: [],
+      narrators: new Set(),
+      languages: new Set(),
+      publishers: new Set(),
+      numIssues: 0
+    }
+
+    if (oldLibrary.isPodcast) {
+      const podcasts = await Database.models.podcast.findAll({
+        include: {
+          model: Database.models.libraryItem,
+          attributes: [],
+          where: {
+            libraryId: oldLibrary.id
+          }
+        },
+        attributes: ['tags', 'genres']
+      })
+      for (const podcast of podcasts) {
+        if (podcast.tags?.length) {
+          podcast.tags.forEach((tag) => data.tags.add(tag))
+        }
+        if (podcast.genres?.length) {
+          podcast.genres.forEach((genre) => data.genres.add(genre))
+        }
+      }
+    } else {
+      const books = await Database.models.book.findAll({
+        include: {
+          model: Database.models.libraryItem,
+          attributes: ['isMissing', 'isInvalid'],
+          where: {
+            libraryId: oldLibrary.id
+          }
+        },
+        attributes: ['tags', 'genres', 'publisher', 'narrators', 'language']
+      })
+      for (const book of books) {
+        if (book.libraryItem.isMissing || book.libraryItem.isInvalid) data.numIssues++
+        if (book.tags?.length) {
+          book.tags.forEach((tag) => data.tags.add(tag))
+        }
+        if (book.genres?.length) {
+          book.genres.forEach((genre) => data.genres.add(genre))
+        }
+        if (book.narrators?.length) {
+          book.narrators.forEach((narrator) => data.narrators.add(narrator))
+        }
+        if (book.publisher) data.publishers.add(book.publisher)
+        if (book.language) data.languages.add(book.language)
+      }
+
+      const series = await Database.models.series.findAll({
+        where: {
+          libraryId: oldLibrary.id
+        },
+        attributes: ['id', 'name']
+      })
+      series.forEach((s) => data.series.push({ id: s.id, name: s.name }))
+
+      const authors = await Database.models.author.findAll({
+        where: {
+          libraryId: oldLibrary.id
+        },
+        attributes: ['id', 'name']
+      })
+      authors.forEach((a) => data.authors.push({ id: a.id, name: a.name }))
+    }
+
+    data.authors = naturalSort(data.authors).asc(au => au.name)
+    data.genres = naturalSort([...data.genres]).asc()
+    data.tags = naturalSort([...data.tags]).asc()
+    data.series = naturalSort(data.series).asc(se => se.name)
+    data.narrators = naturalSort([...data.narrators]).asc()
+    data.publishers = naturalSort([...data.publishers]).asc()
+    data.languages = naturalSort([...data.languages]).asc()
+    data.loadedAt = Date.now()
+    Database.libraryFilterData[oldLibrary.id] = data
+
+    Logger.debug(`Loaded filterdata in ${((Date.now() - start) / 1000).toFixed(2)}s`)
+    return data
   }
 }
\ No newline at end of file
diff --git a/server/utils/queries/libraryItemsBookFilters.js b/server/utils/queries/libraryItemsBookFilters.js
index a0abcc92..67a933b9 100644
--- a/server/utils/queries/libraryItemsBookFilters.js
+++ b/server/utils/queries/libraryItemsBookFilters.js
@@ -914,5 +914,16 @@ module.exports = {
       libraryItem.media = book
       return libraryItem
     })
+  },
+
+  /**
+   * Get library items for series
+   * @param {oldSeries} oldSeries 
+   * @param {[oldUser]} oldUser 
+   * @returns {Promise<oldLibraryItem[]>}
+   */
+  async getLibraryItemsForSeries(oldSeries, oldUser) {
+    const { libraryItems } = await this.getFilteredLibraryItems(oldSeries.libraryId, oldUser, 'series', oldSeries.id, null, null, false, [], null, null)
+    return libraryItems.map(li => Database.models.libraryItem.getOldLibraryItem(li))
   }
 }
\ No newline at end of file