diff --git a/AAXtoMP3 b/AAXtoMP3
index 6021cfb..67417ae 100755
--- a/AAXtoMP3
+++ b/AAXtoMP3
@@ -72,6 +72,18 @@ if ! [[ $(type -P "$GREP") ]]; then
   exit 1
 fi
 
+# -----
+# Detect if we need mp4art for cover additions to m4a & m4b files.
+if [[ "x${extension}" == "xm4a" && "x$(type -P mp4art)" == "x" ]]; then
+  echo "WARN mp4art was not found on your env PATH variable"
+  echo "Without it, this script will not be able to add cover art to"
+  echo "m4b files. Note if there are no other errors the AAXtoMP3 will"
+  echo "continue. However no cover art will be added to the output."
+  echo "INSTALL:" 
+  echo "MacOS:   brew install mp4v2"
+  echo "Ubuntu:  sudo apt-get install mp4v2-utils"
+fi
+
 # -----
 # Obtain the authcode from either the command line,  local directory or home directory.
 # See Readme.md for details on how to aquire your personal authcode for your personal
@@ -273,7 +285,15 @@ do
     log "Done creating chapters. Chaptered files contained in ${output_directory}."
   fi
 
-  # Detect if we are actuall m4b instead of m4a
+  # ----
+  # Add the cover art to m4a and m4b file types.
+  if [[ ${extension} == "m4a" && $(type -P mp4art) ]]; then
+    mp4art --add "${cover_path}" "${full_file_path}"
+    log "Added cover art."
+  fi 
+
+  # ----
+  # Detect if we are actuall m4b instead of m4a Then rename the file.
   if [[ ${extension} == "m4a" && ${container}="m4b" ]]; then
     mv "${full_file_path}" "${full_file_path/.m4a/.m4b}"
   fi
diff --git a/README.md b/README.md
index a27f20e..db91440 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,8 @@ can obtain this string from a tool like [audible-activator](https://github.com/i
 * bash 4.3.42 or later tested
 * ffmpeg version 2.8.3 or later
 * libmp3lame (came from lame package on Arch, not sure where else this is stored)
+* grep Some OS distributions do not have it installed.
+* mp4art used to add cover art to m4a and m4b files. Optional
 
 ## OSX
 Thanks to thibaudcolas, this script has been tested on OSX 10.11.6 El Capitan. YMMV, but it should work for 
@@ -68,6 +70,13 @@ bash AAXtoMP3 [-f|--flac] [-o|--opus] [-a|-aac] [-s|--single] [-e:mp3] [-e:m4a]
 * Can be done by using the **-f** or **--flac** command line switches
 * FLAC is an open format with royalty-free licensing 
 
+### M4A and M4B Containers ###
+* These containers were created by Apple Inc. They were meant to be the successor to mp3.
+* M4A is a container that is meant to hold music and is typically of a higher bitrate.
+* M4B is a container that is meant to hold audiobooks and is typically has bitrates of 64k and 32k.
+* Both formats are chaptered
+* Both support coverart internall
+
 ### Defaults
 * Specifying the AUTHCODE.
     In order of __precidence__.