I've got the Zinn book and, yes, it's great. But I also got "Bike Repair Manual" by Chris Sidwells. It's British book with American printing and cover price of only $15 (vs. about $40 for Zinn, as I recall). (
www.dk.com). I'm mildly dyslexic and find that following any kind of written instruction can be very perplexing. For whatever reason, the Sidwells book is clearer in its explanations for me than the Zinn book without sacrificing depth -- and it offers four-colour photos, instead of Zinn's line drawings. Highly recommended