The thinking person’s book of big answers to small questions. Applying tools for rationality from economics, law, and elsewhere to the everyday puzzles reveals fresh ways to consider problems of any size—including whether to tip for takeout.

Learn how to make better decisions in ordinary life. Does safely driving over the speed limit hurt anyone? Should you be allowed to spy on sports opponents? Is it fair to recline your seat on an airplane? Should you let someone who’s in a hurry cut in line?

Saul Levmore and Ward Farnsworth invite you on a witty, accessible, and insightful tour of life’s little puzzles and ways to understand them better. As the authors show, analyzing common questions is both fun and deeply rewarding.

But this isn’t just a book about practical wisdom to make better choices—it presents a toolkit for a more rational life. Learn how Bayesian updating applies to getting a bad medical test. Discover how optimal-stopping theory applies to making the best choice whether buying a home, looking for a job, or finding the right life partner. See the hidden zero-sum game in buying a lifetime pass to anything.

To paraphrase the authors: Aids to rationality are most enjoyable, and easiest to learn about, when you meet them in familiar settings, so that’s where we’ll see them in action—with many insights along the way about business, politics, and the rest of life.

This is a friendly, funny, and deeply smart compendium devoted to the art of better thinking. It offers food for thought and conversation as well as a way to navigate those “should I” questions that define our lives. The authors’ love of teaching shines through in this fascinating book that you’ll want to read more than once.