UPDATE: *See this list of Best LSAT Prep Books. That's what I'm updating, not the list below.*
*See LSAT study schedules to find out how to use these.*
The Newest LSAT PrepTests
by the Law School Admission Council (LSAC)
The test has significantly changed in the last decade, so make sure you get several of the newer exams.
Use: throughout your exam prep.

The Next 10 Actual, Official LSAT PrepTests
by LSAC (identical older edition)
This book includes PrepTests 29-38. You'll need to get a copy of this to adequately prepare.
Use: during your exam preparation.
(Check out my unofficial LSAT Logic Games questions, which accompany the Logic Games included in this book.)

10 More Actual, Official LSAT PrepTests
by LSAC (identical older edition)
This book includes PrepTests 19-28.
Use: during your exam preparation.

10 Actual Official LSAT PrepTests
by LSAC (identical older edition)
This book includes most of the PrepTests from 7-18. It's only worth your time to do these if you've begun your prep early enough that you will have plenty of time to complete the newer PrepTests also.
Remember: These PrepTests are from 12/1992 - 9/1995. There's no need to worry if you find some of the Logic Games tricky. These game types hardly ever surface on newer exams.
Use (if at all): at the beginning of your preparation to help you get used to the LSAT.

The Oldest LSAT PrepTests
by LSAC
LSAT PrepTests 1-6 (June 1991 - October 1992), 8 (June 1993), and 17 (December 1995) are out-of-print, but available on Amazon.com
Use: if you'll have time to complete the more recent exams as well.

The Official LSAT SuperPrep
by LSAC (identical older edition, except for tiny difference noted below)
This book includes a couple of exams you won't see anywhere else: 2/1996, 2/1999, and 2/2000. However, the book's biggest selling point is the fact that it includes complete explanations of each exam. It's important to know how the test-makers think.
Use: Read the introductory section covering each section of the exam prior to attempting questions of each type in the first few months of your prep. The introductory section is pages 1-62 (in newer edition) or pages 1-54 (in older edition).
(That 8-page difference consists of a comparative reading passage you won't find anywhere else, as well as a detailed explanation of it. This is the only difference between the editions that I spotted.)
Save the 3 exams in the book (and the explanations of each) for later in your preparation. The explanations are rather technical, so you may benefit more from them after working through my Logic Games and Logical Reasoning plans.
However, if SuperPrep's introductory section is smooth sailing for you and you feel like LSAC's writing style doesn't confuse you, then feel free to work through the three exams (and read their explanations) in the same manner that I recommend working through Next 10 in my 3-month sample study schedule.

The Official LSAT Handbook
LSAT Grouped by Logic Game Type
LSAT Grouped by Question Type
Kaplan LSAT Mastery Practice
June 2007 LSAT exam (PDF)
by LSAC
This is a free sample PrepTest. When you're making a study schedule, treat this exam as if it were PrepTest 51 1/2.
Sample LSAT Questions and Explanations (PDF)
by LSAC
From the folks who write the exam. Released in 2008.
About the LSAT
by LSAC
More sample questions and explanations, as well as a great overview of the exam.

A Rulebook for Arguments
by Anthony Weston
If you're only going to order one book for your LSAT prep aside from LSAT-specific books, make this it.
Weston will show you how to spot gaps in arguments and flawed reasoning. His book is clear, simple, and concise (104 pages). It serves as an excellent outline and how-to guide for the LSAT's Logical Reasoning section.
It's a great (and amusing) framework for LSAT-style thinking. It's really cheap (compared to the other books, anyway). Don't buy an older edition of this one to save money, though. The author has improved/added significant content for each new edition.
Use: Before you start studying for the LSAT, or before you start the Logical Reasoning section.

Logic Made Easy: How to Know When Language Deceives You
by Deborah Bennett (older edition)
Even though this book is not specifically written for LSAT prep, it includes many Logical Reasoning-style questions. It also discusses several common fallacies. Bennett is clearly familiar with the LSAT, which makes the book useful for LSAT prep. The book is clearly-written, contains basic examples, and it's concise.
Feel free to skip the chapters on the history of logic (and chapter 10 on truth tables) and focus on the everyday-life examples throughout the book instead. Be sure to check out the section on fallacies in Chapter 11, as well as the final chapter.
Also see my interview with Dr. Bennett on Logic Made Easy.
Use: Before you start studying for the LSAT, or before you start the Logical Reasoning section.

Informal Logic: A Pragmatic Approachby Douglas Walton (older edition)
Clearly demonstrates and explains several types of valid and invalid arguments. Walton loves reviewing logical fallacies, and he discusses several common ones that appear on the LSAT.
Use (if at all): Before you start studying or before you start the Logical Reasoning section.

Elementary Logic: Revised Edition
by William Quine (older edition)
It's only 144 pages, but it manages to cover several fundamental issues in logic, such as necessary and sufficient conditions. If you're interested, and you have enough time, look it up, but you don't need to.
Use (if at all): Before you start preparing or before you start the Logical Reasoning section.

How to Solve It: A New Aspect of Mathematical Method
by George Polya (older editions)
Basic suggestions for logical thinking and problem solving. Why use it? Because it provides a framework you can use to identify and analyze relationships between evidence and conclusion in a given argument. Wikipedia, this summary, and these questions should be enough.
Ask the following questions when you encounter each Logical Reasoning stimulus or Logic Game.
1. What info is provided/unknown? Does the evidence support the conclusion?
2. How does this stimulus/game differ from other ones you've seen?
3. Does restating the argument help? (Consider the contrapositive.)
4. Can you make any inferences from the given information?
5. What can you do with the inferences?
Another good summary.
Use (if at all): Before you start preparing or before you start the Logical Reasoning section.

LSAT Blog's Sudoku Puzzles for LSAT Prep
I've put together 208 easy-to-moderate sudoku puzzles, along with a brief introduction to sudoku. They're presented in increasing order of difficulty.
You can download and print out multiple copies of each puzzle.
Sudoku puzzles will sharpen your brain and prepare it for the Logic Games.
Use (if at all): Before you start studying or when you need a break.
***
See my LSAT Study Schedules for advice on using LSAT PrepTests effectively.
by the Law School Admission Council (LSAC)
The test has significantly changed in the last decade, so make sure you get several of the newer exams.
Use: throughout your exam prep.

The Next 10 Actual, Official LSAT PrepTests
by LSAC (identical older edition)
This book includes PrepTests 29-38. You'll need to get a copy of this to adequately prepare.
Use: during your exam preparation.
(Check out my unofficial LSAT Logic Games questions, which accompany the Logic Games included in this book.)
10 More Actual, Official LSAT PrepTests
by LSAC (identical older edition)
This book includes PrepTests 19-28.
Use: during your exam preparation.
10 Actual Official LSAT PrepTests
by LSAC (identical older edition)
This book includes most of the PrepTests from 7-18. It's only worth your time to do these if you've begun your prep early enough that you will have plenty of time to complete the newer PrepTests also.
Remember: These PrepTests are from 12/1992 - 9/1995. There's no need to worry if you find some of the Logic Games tricky. These game types hardly ever surface on newer exams.
Use (if at all): at the beginning of your preparation to help you get used to the LSAT.

The Oldest LSAT PrepTests
by LSAC
LSAT PrepTests 1-6 (June 1991 - October 1992), 8 (June 1993), and 17 (December 1995) are out-of-print, but available on Amazon.com
Use: if you'll have time to complete the more recent exams as well.
The Official LSAT SuperPrep
by LSAC (identical older edition, except for tiny difference noted below)
This book includes a couple of exams you won't see anywhere else: 2/1996, 2/1999, and 2/2000. However, the book's biggest selling point is the fact that it includes complete explanations of each exam. It's important to know how the test-makers think.
Use: Read the introductory section covering each section of the exam prior to attempting questions of each type in the first few months of your prep. The introductory section is pages 1-62 (in newer edition) or pages 1-54 (in older edition).
(That 8-page difference consists of a comparative reading passage you won't find anywhere else, as well as a detailed explanation of it. This is the only difference between the editions that I spotted.)
Save the 3 exams in the book (and the explanations of each) for later in your preparation. The explanations are rather technical, so you may benefit more from them after working through my Logic Games and Logical Reasoning plans.
However, if SuperPrep's introductory section is smooth sailing for you and you feel like LSAC's writing style doesn't confuse you, then feel free to work through the three exams (and read their explanations) in the same manner that I recommend working through Next 10 in my 3-month sample study schedule.

The Official LSAT Handbook
LSAT Grouped by Logic Game Type
LSAT Grouped by Question Type
Kaplan LSAT Mastery Practice
June 2007 LSAT exam (PDF)
by LSAC
This is a free sample PrepTest. When you're making a study schedule, treat this exam as if it were PrepTest 51 1/2.
Sample LSAT Questions and Explanations (PDF)
by LSAC
From the folks who write the exam. Released in 2008.
About the LSAT
by LSAC
More sample questions and explanations, as well as a great overview of the exam.

A Rulebook for Arguments
by Anthony Weston
If you're only going to order one book for your LSAT prep aside from LSAT-specific books, make this it.
Weston will show you how to spot gaps in arguments and flawed reasoning. His book is clear, simple, and concise (104 pages). It serves as an excellent outline and how-to guide for the LSAT's Logical Reasoning section.
It's a great (and amusing) framework for LSAT-style thinking. It's really cheap (compared to the other books, anyway). Don't buy an older edition of this one to save money, though. The author has improved/added significant content for each new edition.
Use: Before you start studying for the LSAT, or before you start the Logical Reasoning section.
Logic Made Easy: How to Know When Language Deceives You
by Deborah Bennett (older edition)
Even though this book is not specifically written for LSAT prep, it includes many Logical Reasoning-style questions. It also discusses several common fallacies. Bennett is clearly familiar with the LSAT, which makes the book useful for LSAT prep. The book is clearly-written, contains basic examples, and it's concise.
Feel free to skip the chapters on the history of logic (and chapter 10 on truth tables) and focus on the everyday-life examples throughout the book instead. Be sure to check out the section on fallacies in Chapter 11, as well as the final chapter.
Also see my interview with Dr. Bennett on Logic Made Easy.
Use: Before you start studying for the LSAT, or before you start the Logical Reasoning section.
Informal Logic: A Pragmatic Approachby Douglas Walton (older edition)
Clearly demonstrates and explains several types of valid and invalid arguments. Walton loves reviewing logical fallacies, and he discusses several common ones that appear on the LSAT.
Use (if at all): Before you start studying or before you start the Logical Reasoning section.
Elementary Logic: Revised Edition
by William Quine (older edition)
It's only 144 pages, but it manages to cover several fundamental issues in logic, such as necessary and sufficient conditions. If you're interested, and you have enough time, look it up, but you don't need to.
Use (if at all): Before you start preparing or before you start the Logical Reasoning section.
How to Solve It: A New Aspect of Mathematical Method
by George Polya (older editions)
Basic suggestions for logical thinking and problem solving. Why use it? Because it provides a framework you can use to identify and analyze relationships between evidence and conclusion in a given argument. Wikipedia, this summary, and these questions should be enough.
Ask the following questions when you encounter each Logical Reasoning stimulus or Logic Game.
1. What info is provided/unknown? Does the evidence support the conclusion?
2. How does this stimulus/game differ from other ones you've seen?
3. Does restating the argument help? (Consider the contrapositive.)
4. Can you make any inferences from the given information?
5. What can you do with the inferences?
Another good summary.
Use (if at all): Before you start preparing or before you start the Logical Reasoning section.

LSAT Blog's Sudoku Puzzles for LSAT Prep
I've put together 208 easy-to-moderate sudoku puzzles, along with a brief introduction to sudoku. They're presented in increasing order of difficulty.
You can download and print out multiple copies of each puzzle.
Sudoku puzzles will sharpen your brain and prepare it for the Logic Games.
Use (if at all): Before you start studying or when you need a break.
***
See my LSAT Study Schedules for advice on using LSAT PrepTests effectively.









