Your LSAT score is the most important part of the law school admissions process.
The test has been changing recently; these are the most representative of what you'll see on test day.
However, if you just need one section, the individual book links are below too.
The LSAT is an aptitude test.
Like all aptitude tests, it must choose a medium in which to measure intellectual ability.
Although this makes the LSAT hard, it also makes the test predictable--it is based on fundamental principles of logic.