I have The National Audubon Society's pocket guide to familiar Reptiles and Amphibians of North America. Its not a herpetological textbook by any means, but it fits in your pocket and has some great advice regarding our friends the venomous snakes ( namely leave them the heck alone ). Its even got a little section on when, where, and how to find wild herps. Can't say I've ever used it in the "wild", but it seems like it would be handy.