Radiolab. It is a podcast, not an audio book, but I would recommend downloading the entire set at http://feeds.wnyc.org/radiolab and listening to all of them.

Listen to them in order, oldest to newest. I would not recommend starting with the most recent "Jad and Robert: The Early Years" which is mainly about the hosts.

And if you want to cherrypick one show to start with try: Musical Language.