Everyone has their "thing" that they collect, even if they won't acknowledge that they're a collector. If you've got more than four shot glasses, you're a shot glass collector. If you've got more than a handful of coffee mugs, you're a coffee mug collector. If you have more than three pairs of sneakers, you're a full-fledged sneaker collector. Sorry, bro. You are.
And for the sneakerhead in your life (whether he acknowledges it or not), there's Out of the Box: The Rise of Sneaker Culture ($40, Amazon). A painstakingly researched book that details the very first sneaker (a spiked running shoe from 1860) all the way up to modern-day kicks.