diff --git a/BookPlayer/Extensions/Notification+BookPlayer.swift b/BookPlayer/Extensions/Notification+BookPlayer.swift
index 4381b473c..939f2d705 100644
--- a/BookPlayer/Extensions/Notification+BookPlayer.swift
+++ b/BookPlayer/Extensions/Notification+BookPlayer.swift
@@ -14,7 +14,7 @@ extension Notification.Name {
     public static let importOperation = Notification.Name("com.tortugapower.audiobookplayer.operation.new")
     public static let requestReview = Notification.Name("com.tortugapower.audiobookplayer.requestreview")
     public static let updatePercentage = Notification.Name("com.tortugapower.audiobookplayer.book.percentage")
-    public static let updateChapter = Notification.Name("com.tortugapower.audiobookplayer.book.chapter")
+    public static let chapterChange = Notification.Name("com.tortugapower.audiobookplayer.book.chapter")
     public static let bookReady = Notification.Name("com.tortugapower.audiobookplayer.book.ready")
     public static let bookPlayed = Notification.Name("com.tortugapower.audiobookplayer.book.play")
     public static let bookPaused = Notification.Name("com.tortugapower.audiobookplayer.book.pause")
diff --git a/BookPlayer/Models/Book+CoreDataClass.swift b/BookPlayer/Models/Book+CoreDataClass.swift
index 171344609..b1ccc19c3 100644
--- a/BookPlayer/Models/Book+CoreDataClass.swift
+++ b/BookPlayer/Models/Book+CoreDataClass.swift
@@ -20,17 +20,7 @@ public class Book: LibraryItem {
         return self.title + "." + self.ext
     }
 
-    var currentChapter: Chapter? {
-        guard let chapters = self.chapters?.array as? [Chapter], !chapters.isEmpty else {
-            return nil
-        }
-
-        for chapter in chapters where chapter.start <= self.currentTime && chapter.end > self.currentTime {
-            return chapter
-        }
-
-        return nil
-    }
+    var currentChapter: Chapter?
 
     var displayTitle: String {
         return self.title
@@ -72,6 +62,8 @@ public class Book: LibraryItem {
                 self.addToChapters(chapter)
             }
         }
+
+        self.currentChapter = self.chapters?.array.first as? Chapter
     }
 
     convenience init(from bookUrl: FileItem, context: NSManagedObjectContext) {
@@ -113,6 +105,24 @@ public class Book: LibraryItem {
         }
     }
 
+    public override func awakeFromFetch() {
+        super.awakeFromFetch()
+
+        self.updateCurrentChapter()
+    }
+
+    func updateCurrentChapter() {
+        guard let chapters = self.chapters?.array as? [Chapter], !chapters.isEmpty else {
+            return
+        }
+
+        guard let currentChapter = (chapters.first { (chapter) -> Bool in
+            chapter.start <= self.currentTime && chapter.end > self.currentTime
+        }) else { return }
+
+        self.currentChapter = currentChapter
+    }
+
     override func getBookToPlay() -> Book? {
         return self
     }
diff --git a/BookPlayer/Player/PlayerManager.swift b/BookPlayer/Player/PlayerManager.swift
index c33e11b66..ddd80aa01 100644
--- a/BookPlayer/Player/PlayerManager.swift
+++ b/BookPlayer/Player/PlayerManager.swift
@@ -122,6 +122,12 @@ class PlayerManager: NSObject {
             NotificationCenter.default.post(name: .bookEnd, object: nil)
         }
 
+        if let currentChapter = book.currentChapter,
+            book.currentTime > currentChapter.end || book.currentTime < currentChapter.start {
+            book.updateCurrentChapter()
+            NotificationCenter.default.post(name: .chapterChange, object: nil, userInfo: nil)
+        }
+
         let userInfo = [
             "time": currentTime,
             "fileURL": book.fileURL
@@ -159,13 +165,9 @@ class PlayerManager: NSObject {
         }
 
         set {
-            guard let player = self.audioPlayer else {
-                return
-            }
+            guard let player = self.audioPlayer else { return }
 
             player.currentTime = newValue
-
-            self.currentBook?.currentTime = newValue
         }
     }
 
@@ -236,9 +238,7 @@ class PlayerManager: NSObject {
     // MARK: - Seek Controls
 
     func jumpTo(_ time: Double, fromEnd: Bool = false) {
-        guard let player = self.audioPlayer else {
-            return
-        }
+        guard let player = self.audioPlayer else { return }
 
         player.currentTime = min(max(fromEnd ? player.duration - time : time, 0), player.duration)
 
@@ -250,9 +250,7 @@ class PlayerManager: NSObject {
     }
 
     func jumpBy(_ direction: Double) {
-        guard let player = self.audioPlayer else {
-            return
-        }
+        guard let player = self.audioPlayer else { return }
 
         player.currentTime += direction
 
@@ -373,9 +371,7 @@ class PlayerManager: NSObject {
 
     // Toggle play/pause of book
     func playPause(autoplayed _: Bool = false) {
-        guard let audioplayer = self.audioPlayer else {
-            return
-        }
+        guard let audioplayer = self.audioPlayer else { return }
 
         // Pause player if it's playing
         if audioplayer.isPlaying {
diff --git a/BookPlayer/Player/SleepTimer.swift b/BookPlayer/Player/SleepTimer.swift
index 39129c530..fb2746679 100644
--- a/BookPlayer/Player/SleepTimer.swift
+++ b/BookPlayer/Player/SleepTimer.swift
@@ -61,6 +61,13 @@ final class SleepTimer {
             }))
         }
 
+        self.alert.addAction(UIAlertAction(title: "End of current chapter", style: .default) { _ in
+            self.cancel()
+            self.alert.message = "Sleeping when the chapter ends"
+            NotificationCenter.default.addObserver(self, selector: #selector(self.end), name: .chapterChange, object: nil)
+            NotificationCenter.default.addObserver(self, selector: #selector(self.end), name: .bookChange, object: nil)
+        })
+
         self.alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
     }
 
@@ -80,6 +87,8 @@ final class SleepTimer {
         self.alert.message = defaultMessage
 
         self.timer?.invalidate()
+        NotificationCenter.default.removeObserver(self, name: .bookEnd, object: nil)
+        NotificationCenter.default.removeObserver(self, name: .chapterChange, object: nil)
     }
 
     private func cancel() {
@@ -96,12 +105,16 @@ final class SleepTimer {
         self.alert.message = "Sleeping in \(self.durationFormatter.string(from: self.timeLeft)!)"
 
         if self.timeLeft <= 0 {
-            self.timer?.invalidate()
-
-            self.onEnd?(false)
+            self.end()
         }
     }
 
+    @objc private func end() {
+        self.reset()
+
+        self.onEnd?(false)
+    }
+
     // MARK: Public methods
 
     func actionSheet(onStart: @escaping SleepTimerStart, onProgress: @escaping SleepTimerProgress, onEnd: @escaping SleepTimerEnd) -> UIAlertController {