I started my collection many years ago, when literature was a lot more prevalent than it is today. A great many of what I stashed have been out of print for a while, but you can still find copies on eBay, Amazon, the internet, and a lot of later stuff in various catalog houses like Classic and Camaro Central.
A couple in particular: one is Jerry MacNeish's "1969 Definitive Facts Book" covering '69 Z28 and SS396/Copo/Yenko cars, and another might be " Camaro ! Chevy's Classy Chassis", The latter covers multiple model years, but is a decent general info book. Michael Lamm's "The Great Camaro" is also a great collectible, great pics (and available from Amazon). I'm certain you'll have other opinions to add to these -
I made a pass through a major chain bookstore a few months back (nameless, of course), searched the thing from top to bottom without seeing a single piece of literature featuring Camaros of any vintage. Really disappointing, but believable considering what the internet and computers have done to our reference efforts. Good luck, keep your eyes open -
Regards,
Steve