X-link to the Comics thread for a bundle with some non-fiction content:
Humble Comics Bundle IDW Creator Showcase has just one non-fiction title in it, but it's a really good one available at the $1 minimum tier, and which I highly recommend.
The Comic Book History of Comics by Fred Van Lente and Ryan Dunlavey is Exactly What It Says In The Title, and provides well-researched and very readable stories about the roots and influential creators and other figures (such as Fredric Wertham (
Wikipedia) who led the pearl-clutching moral crusade about comics being a bad influence upon the kiddies in the 1950s) around the world, in comic-book format. There's Jack Kirby, Hergé, Osamu Tezuka, Roy Lichenstein, Stan Lee, Will Eisner, Alan Moore, and many more, as well as general anecdotes about the medium and industry.
From the looks of it, this is a collection of the B&W original series (there's also a coloured remastered reprint which I have as a wishlist pre-order in paperback).