"A marvelous book… thought provoking and highly entertaining."

—Jerome Groopman, New York Times bestselling author of How Doctors Think

"Ariely not only gives us a great read; he also makes us much wiser."

—George Akerlof, 2001 Nobel Laureate in Economics

"Revolutionary."

—New York Times Book Review

Why do our headaches persist after we take a one-cent aspirin but disappear when we take a fifty-cent aspirin? Why do we splurge on a lavish meal but cut coupons to save twenty-five cents on a can of soup?

When it comes to making decisions in our lives, we think we're making smart, rational choices. But are we?

In this newly revised and expanded edition of the groundbreaking New York Times bestseller, Dan Ariely refutes the common assumption that we behave in fundamentally rational ways. From drinking coffee to losing weight, from buying a car to choosing a romantic partner, we consistently overpay, underestimate, and procrastinate. Yet these misguided behaviors are neither random nor senseless. They're systematic and predictable—making us predictably irrational.

This landmark book in psychology and economics uncovers the hidden forces that shape our decisions:

• The Power of Price: Discover why a 50-cent aspirin can cure a headache that a one-cent aspirin can’t.
• Behavioral Economics: Learn why we splurge on a lavish meal but cut coupons to save twenty-five cents on a can of soup.
• The Cost of Social Norms: Understand the surprising reasons we are happy to do things for free but not when we are paid to do them.
• The Problem with Procrastination: Explore the struggles with self-control that cause us to consistently overpay, underestimate, and put things off.