diff --git a/to-m4b.sh b/to-m4b.sh
index e282b13..540d0b0 100755
--- a/to-m4b.sh
+++ b/to-m4b.sh
@@ -195,31 +195,30 @@ main() {
 
   if ((${#dirs[@]})); then
     for dir in "${dirs[@]}"; do
-      eval "$(parse-vars "$dir")"
-      if [[ -z "$title" ]]; then
-        echo "Skipping '$dir': could not parse title" >&2
+      eval "$(parse-vars "${dir}")"
+      if [[ -z "${title}" ]]; then
+        echo "Skipping '${dir}': could not parse title" >&2
         continue
       fi
-    if [[ -z "$author" ]]; then
-      echo "Skipping '$dir': could not parse author" >&2
+    if [[ -z "${author}" ]]; then
+      echo "Skipping '${dir}': could not parse author" >&2
       continue
     fi
-    # Construct output path: ${OUT}/<author>/<series or standalone>/<series_index - >title {narrator}.m4b
-    if [[ -n "$series" ]]; then
-      output_file="${out_root}/${author}/${series}/"
-      [[ -n "$series_index" ]] && output_file+="Book ${series_index} - "
-      [[ -n "$year" ]] && output_file+="${year} - "
-      output_file+="${title}"
+    # Construct output path
+    output_file="${out_root}/${author}/"
+    if [[ -n "${series}" && -n "${series_index}" ]]; then
+      output_file+="${series}/Book ${series_index} - ${year} - ${title}"
+      
     else
-      output_file="${out_root}/${author}/"
-      [[ -n "$year" ]] && output_file+="${year} - "
-      output_file+="${title}"
+      output_file+="${year} - ${title}"
+      [[ -n "${narrator}" ]] && output_file+=" {${narrator}}/"
     fi
-    [[ -n "$narrator" ]] && output_file+=" {${narrator}}"
+    output_file+="/${year} - ${title}"
+    [[ -n "${narrator}" ]] && output_file+=" {${narrator}}"
     output_file+=".m4b"
 
-      echo "Processing '$dir' -> '$output_file'"
-      m4b-merge "$output_file" "$dir" "$author" "$narrator" "$title" "$year" "$series" "$series_index"
+      echo "Processing '${dir}' -> '${output_file}'"
+      m4b-merge "${output_file}" "${dir}" "${author}" "${narrator}" "${title}" "${year}" "${series}" "${series_index}"
     done
   else
     echo "No book directories found under '${src_root}'." >&2