beware of "simulated" practice lsat books!
i am writing this opinion so that others can avoid a mistake i made. i bought an lsat test prep book at a bookstore which offered 6 sample lsat s. these were supposedly of the same style and length of the actual lsat, so i thought i was getting an accurate idea of how i would do on the real test based on my practice test scores. later, i purchased from the lsac a book containing 10 actual lsat tests used in the past. let me just say, my score was much lower on these than they had been on the sample tests! i have found, by talking to others, that this tends to be a common experience.
the sample test books do have a feature not found with the old tests bought from the lsac, and that is detailed explanations of answers to each individual question. this helps, when starting out, to identify and correct problems with certain types of questions. in addition, these books offer more in depth strategies to answering the questions than that which is offered by the lsac.
my advice? the sample test prep books are a good place to start familiarizing yourself with the test format and basic types of questions, but i would highly recommend taking at least a few of the actual older tests in order to get a more accurate idea of how you will fare come test day. good luck!