Thinking, Fast and Slow is a book by psychologist Daniel Kahneman that explores the two systems of thought that drive human behavior: System 1, which is fast, intuitive, and emotional; and System 2, which is slower, more deliberate, and more logical.
Kahneman explains how System 1 is responsible for our ability to make quick decisions in everyday life, while System 2 is responsible for more complex tasks such as planning and problem-solving. He also discusses how our two systems of thought can interact in ways that can lead to errors in judgment and decision-making.