Courtesy of Chris Albon, who writes:

Hi SWJ,

I am a avid reader of SWJ. I stumbled upon two free audiobooks that
might interest SWJ readers:

The History of the Peloponnesian War

http://librivox.org/the-history-of-the-peloponnesian-war-by-thucydides/

The Art of War.

http://librivox.org/the-art-of-war-by-sun-tzu/

There are entirely free, downloadable audiobooks.