diff --git a/server/ApiController.js b/server/ApiController.js
index cfd99cac..2fe3315d 100644
--- a/server/ApiController.js
+++ b/server/ApiController.js
@@ -15,6 +15,7 @@ const BackupController = require('./controllers/BackupController')
 
 const BookFinder = require('./BookFinder')
 const AuthorFinder = require('./AuthorFinder')
+const FileSystemController = require('./controllers/FileSystemController')
 
 class ApiController {
   constructor(MetadataPath, db, auth, streamManager, rssFeeds, downloadManager, coverController, backupManager, watcher, cacheManager, emitter, clientEmitter) {
@@ -145,6 +146,11 @@ class ApiController {
     this.router.get('/search/covers', this.findCovers.bind(this))
     this.router.get('/search/books', this.findBooks.bind(this))
 
+    //
+    // File System Routes
+    //
+    this.router.get('/filesystem', FileSystemController.getPaths.bind(this))
+
     //
     // Others
     //
@@ -163,8 +169,6 @@ class ApiController {
 
     this.router.get('/download/:id', this.download.bind(this))
 
-    this.router.get('/filesystem', this.getFileSystemPaths.bind(this))
-
     this.router.post('/syncUserAudiobookData', this.syncUserAudiobookData.bind(this))
 
     this.router.post('/purgecache', this.purgeCache.bind(this))
@@ -339,25 +343,6 @@ class ApiController {
     }
   }
 
-  async getFileSystemPaths(req, res) {
-    var excludedDirs = ['node_modules', 'client', 'server', '.git', 'static', 'build', 'dist', 'metadata', 'config', 'sys', 'proc'].map(dirname => {
-      return Path.sep + dirname
-    })
-
-    // Do not include existing mapped library paths in response
-    this.db.libraries.forEach(lib => {
-      lib.folders.forEach((folder) => {
-        var dir = folder.fullPath
-        if (dir.includes(global.appRoot)) dir = dir.replace(global.appRoot, '')
-        excludedDirs.push(dir)
-      })
-    })
-
-    Logger.debug(`[Server] get file system paths, excluded: ${excludedDirs.join(', ')}`)
-    var dirs = await this.getDirectories(global.appRoot, '/', excludedDirs)
-    res.json(dirs)
-  }
-
   async syncUserAudiobookData(req, res) {
     if (!req.body.data) {
       return res.status(403).send('Invalid local user audiobook data')
diff --git a/server/controllers/FileSystemController.js b/server/controllers/FileSystemController.js
new file mode 100644
index 00000000..28d63571
--- /dev/null
+++ b/server/controllers/FileSystemController.js
@@ -0,0 +1,25 @@
+const Logger = require('../Logger')
+
+class FileSystemController {
+  constructor() { }
+
+  async getPaths(req, res) {
+    var excludedDirs = ['node_modules', 'client', 'server', '.git', 'static', 'build', 'dist', 'metadata', 'config', 'sys', 'proc'].map(dirname => {
+      return Path.sep + dirname
+    })
+
+    // Do not include existing mapped library paths in response
+    this.db.libraries.forEach(lib => {
+      lib.folders.forEach((folder) => {
+        var dir = folder.fullPath
+        if (dir.includes(global.appRoot)) dir = dir.replace(global.appRoot, '')
+        excludedDirs.push(dir)
+      })
+    })
+
+    Logger.debug(`[Server] get file system paths, excluded: ${excludedDirs.join(', ')}`)
+    var dirs = await this.getDirectories(global.appRoot, '/', excludedDirs)
+    res.json(dirs)
+  }
+}
+module.exports = new FileSystemController()
\ No newline at end of file
diff --git a/server/controllers/LibraryController.js b/server/controllers/LibraryController.js
index f0963cef..0980b156 100644
--- a/server/controllers/LibraryController.js
+++ b/server/controllers/LibraryController.js
@@ -189,12 +189,9 @@ class LibraryController {
     if (!audiobooks.length) {
       return res.status(404).send('Series not found')
     }
-    audiobooks = sort(audiobooks).asc(ab => {
-      if (!isNaN(ab.book.volumeNumber) && ab.book.volumeNumber !== null) return Number(ab.book.volumeNumber)
-      return ab.book.volumeNumber
-    })
+    var sortedBooks = libraryHelpers.sortSeriesBooks(audiobooks, false)
     res.json({
-      results: audiobooks.map(ab => ab.toJSONExpanded()),
+      results: sortedBooks,
       total: audiobooks.length
     })
   }
diff --git a/server/utils/libraryHelpers.js b/server/utils/libraryHelpers.js
index 10bb4af4..2d012587 100644
--- a/server/utils/libraryHelpers.js
+++ b/server/utils/libraryHelpers.js
@@ -1,4 +1,7 @@
-const { sort } = require('fast-sort')
+const { sort, createNewSortInstance } = require('fast-sort')
+const naturalSort = createNewSortInstance({
+  comparer: new Intl.Collator(undefined, { numeric: true, sensitivity: 'base' }).compare
+})
 
 module.exports = {
   decode(text) {
@@ -92,14 +95,18 @@ module.exports = {
       }
     })
     return Object.values(_series).map((series) => {
-      series.books = sort(series.books).asc(ab => {
-        if (!isNaN(ab.book.volumeNumber) && ab.book.volumeNumber !== null) return Number(ab.book.volumeNumber)
-        return ab.book.volumeNumber
-      })
+      series.books = naturalSort(series.books).asc(ab => ab.book.volumeNumber)
       return series
     })
   },
 
+  sortSeriesBooks(books, minified = false) {
+    return naturalSort(books).asc(ab => ab.book.volumeNumber).map(ab => {
+      if (minified) return ab.toJSONMinified()
+      return ab.toJSONExpanded()
+    })
+  },
+
   getBooksWithUserAudiobook(user, books) {
     return books.map(book => {
       return {