In typically thorough Haynes manual detail, the MGB edition will enable the weekend hobbyist to become a weekend mechanic. If you're looking for buying tips and historical context, you won't find it here... the book is entirely devoted to removing, repairing, and replacing just about every serviceable component of the car - from the engine and transmission to the windshield washer motor. You should know which end of a screwdriver is up, as the book is long on the "what to do" but short, at times, on exactly how to go about doing it. The exploded parts diagrams alone are worth the price of the book.
The bodywork section is generalized - get Lindsay Porter's DIY guide for that. For the mechanical systems which make your car go, these are the best twelve dollars you can spend - don't leave home without it.