This book introduces readers to “cognitive economics,” a rapidly emerging interdisciplinary science built on economic, psychological, and data scientific foundations. Throughout the book, economist Andrew Caplin provides new approaches to help scholars collaborate and solve problems that can shape economic outcomes and bridge the gap between theoretical knowledge and the real world. Divided into two parts, the first section brings readers up to speed on economic concepts that underlie decision-making mistakes, such as utility functions, subjective beliefs, and costs of learning. It also explores real-world applications, including improvements in legal decision-making, online privacy protection, and optimizing human-AI collaboration.