The Lady Mechanic's Total Car Care for the Clueless : A Manual for Car Owners by Ren Volpe, ISBN: 0312187335, paperback.

Buy this book if you don't know what to do with your car besides put more gas in it and wash it once in a while. Written by "the lady mechanic," it is not as overly ambitious as most car repair manuals (you will not be rebuilding the engine), but it's not too dumbed down either. Should you get really interested in the innards of you car, she provides you with the vocabulary to get started. For the rest of us, though, the book tells you how to do all the things you should know how to do already. The language is clear enough and the index blissfully good enough that you should really read the thing through once or twice and then put it in your glove box and keep it there for when weird things happen on the road. Get a copy for everyone you know who might need it: your mom who drives to work by herself, your geeky little brother who just got his license, your girlfriend, anyone you care about and would like to be safe and informed.

PS: No, I am not related to the author. I just think it's a marvelous little book.