diff --git a/CHANGELOG.md b/CHANGELOG.md
index d3d73b8..93f5ede 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1 +1,2 @@
-- Better approach for detemining the correct configuration folder for Linux and MacOS, using platformdirs.
\ No newline at end of file
+- Added support for chapter metadata in m4b audio files, enabling proper chapter navigation in audiobooks. Special thanks to @jborza for implementing this feature in PR #10.
+- Better approach for determining the correct configuration folder for Linux and MacOS, using platformdirs.
\ No newline at end of file
diff --git a/abogen/conversion.py b/abogen/conversion.py
index 2e2610b..0612e0c 100644
--- a/abogen/conversion.py
+++ b/abogen/conversion.py
@@ -12,6 +12,7 @@ from utils import clean_text
 from constants import PROGRAM_NAME, LANGUAGE_DESCRIPTIONS, SAMPLE_VOICE_TEXTS
 from voice_formulas import get_new_voice
 import static_ffmpeg
+import threading  # for efficient waiting
 
 def get_sample_voice_text(lang_code):
     return SAMPLE_VOICE_TEXTS.get(lang_code, SAMPLE_VOICE_TEXTS["a"])
@@ -128,6 +129,7 @@ class ConversionThread(QThread):
         use_gpu=True,
     ):  # Add use_gpu parameter
         super().__init__()
+        self._chapter_options_event = threading.Event()
         self.np = np_module
         self.KPipeline = kpipeline_class
         self.file_name = file_name
@@ -252,18 +254,12 @@ class ConversionThread(QThread):
                 and not self.chapter_options_set
             ):
 
-                self.waiting_for_user_input = True
-                # Emit signal to main thread to show dialog
+                # Emit signal to main thread and wait
                 self.chapters_detected.emit(total_chapters)
-
-                # Wait for chapter options to be set
-                while self.waiting_for_user_input and not self.cancel_requested:
-                    time.sleep(0.1)
-
+                self._chapter_options_event.wait()
                 if self.cancel_requested:
                     self.conversion_finished.emit("Cancelled", None)
                     return
-
                 self.chapter_options_set = True
 
             # Log all detected chapters at the beginning
@@ -607,6 +603,7 @@ class ConversionThread(QThread):
         self.save_chapters_separately = options["save_chapters_separately"]
         self.merge_chapters_at_end = options["merge_chapters_at_end"]
         self.waiting_for_user_input = False
+        self._chapter_options_event.set()
 
     def _generate_m4b_with_chapters(self, out_path, chapters_time):
         # generate chapters.txt in the same folder as the output file
diff --git a/abogen/gui.py b/abogen/gui.py
index 95ba0e2..b5780db 100644
--- a/abogen/gui.py
+++ b/abogen/gui.py
@@ -670,13 +670,18 @@ class abogen(QWidget):
         format_layout = QVBoxLayout()
         format_layout.addWidget(QLabel("Output Format:", self))
         self.format_combo = QComboBox(self)
-        self.format_combo.setStyleSheet(
-            "QComboBox { min-height: 20px; padding: 6px 12px; }"
+        self.format_combo.setStyleSheet("QComboBox { min-height: 20px; padding: 6px 12px; }")
+        # Add items with display labels and underlying keys
+        for key, label in [("wav","wav"),("flac","flac"),("mp3","mp3"),("m4b","m4b (with chapters)")]:
+            self.format_combo.addItem(label, key)
+        # Initialize selection by matching saved key
+        idx = self.format_combo.findData(self.selected_format)
+        if idx >= 0:
+            self.format_combo.setCurrentIndex(idx)
+        # Map selection back to key on change
+        self.format_combo.currentIndexChanged.connect(
+            lambda i: self.on_format_changed(self.format_combo.itemData(i))
         )
-        format_options = ["wav", "flac", "mp3", "m4b"]
-        self.format_combo.addItems(format_options)
-        self.format_combo.setCurrentText(self.selected_format)
-        self.format_combo.currentTextChanged.connect(self.on_format_changed)
         format_layout.addWidget(self.format_combo)
         controls_layout.addLayout(format_layout)
         # Save location