A very thorough, explicit, step-by-step guide to what law school professors want to see on your written exams. Very lucid, sometimes even witty. Most law schools still adhere to the Socratic, sink-or-swim method, in which students are kept in the dark about what's expected of them. As a result, many students are totally flummoxed and panic-stricken when exam time rolls around. Be sure to read this book just before you head off to law school; then read it again a couple of weeks before your first exam. If you follow the authors' advice, you are practically guaranteed good grades. Hey, you might even make the Law Review. It worked for me.
Other good books to read before heading off to law school:
Law 101, by Jay Feinman
Introduction to U.S. Legal System, by William Burnham
Planet Law School, by "Atticus Falcon"
The first two give a nice overview of the whole subject and will help you tie everything together. The last is an overcynical but very amusing description of the kind of mind games you're likely to encounter; it also contains the best study tips I've seen.
Also: If you have the time and money, enroll in an intensive paralegal training course before law school. I did, and it really saved my ass during 1L.
Last but definitely not least: Spend at least six months prepping HARD for the LSAT. Work your way through a good logic textbook (I recommend Copi's), study a good prep book (e.g., Jeff Kolby's), and practice on as many real LSATs as you can, under time-pressured conditions. It really pays off.