Thinking, Fast and Slow is a landmark book in psychology and behavioral economics that explains how the human mind makes decisions through two distinct modes of thinking. Daniel Kahneman describes System 1, which is fast, intuitive, and automatic, and System 2, which is slow, deliberate, and analytical. Drawing on decades of research, he explores cognitive biases, heuristics, overconfidence, loss aversion, framing effects, and the ways these mental shortcuts influence judgment and decision-making in everyday life. The book offers practical insights into improving critical thinking, making better decisions, and understanding the strengths and limitations of human reasoning.