diff --git a/mp3s-to-m4b.sh b/mp3s-to-m4b.sh
new file mode 100644
index 0000000..729671f
--- /dev/null
+++ b/mp3s-to-m4b.sh
@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+
+set -e
+
+OUTPUT="audiobook.m4b"
+FILES="files.txt"
+CHAPTERS="chapters.txt"
+
+# list of MP3 files in filename order
+find . -maxdepth 1 -name '*.mp3' -print0 |
+    sort -z |
+    while IFS= read -r -d '' file; do
+        file="${file#./}"
+        printf "file '%s'\n" "$file"
+    done > "$FILES"
+
+# start chapter metadata file
+{
+    echo ";FFMETADATA1"
+} > "$CHAPTERS"
+
+START=0
+
+while IFS= read -r line; do
+    FILE="${line#file \'}"
+    FILE="${FILE%\'}"
+
+    # duration in milliseconds
+    DURATION=$(ffprobe \
+        -v error \
+        -show_entries format=duration \
+        -of csv=p=0 \
+        "$FILE")
+
+    DURATION_MS=$(awk "BEGIN {printf \"%.0f\", $DURATION * 1000}")
+    END=$((START + DURATION_MS))
+
+    # filename as the chapter title
+    TITLE="${FILE%.mp3}"
+
+    cat >> "$CHAPTERS" <<EOF
+[CHAPTER]
+TIMEBASE=1/1000
+START=$START
+END=$END
+title=$TITLE
+EOF
+
+    START=$END
+
+done < "$FILES"
+
+read -p "Press Enter key after making any corrections to $CHAPTERS"
+
+ffmpeg \
+    -f concat \
+    -safe 0 \
+    -i "$FILES" \
+    -i "$CHAPTERS" \
+    -map 0:a \
+    -map_metadata 1 \
+    -c:a aac \
+    -b:a 128k \
+    -movflags +faststart \
+    "$OUTPUT"