A “wonderfully smart and readable” (Washington Post) book that combines philosophical wisdom and scientific research, revealing surprising insights about how to live a meaningful life The Happiness Hypothesis is a book about ten Great Ideas. Each chapter is an attempt to savor one idea that has been discovered by several of the world's civilizations—to question it in light of what we now know from scientific research, and to extract from it the lessons that still apply to our modern lives and illuminate the causes of human flourishing. Award-winning psychologist Jonathan Haidt shows how a deeper understanding of the world's philosophical wisdom and its enduring maxims—like "do unto others as you would have others do unto you," or "what doesn't kill you makes you stronger"—can enrich and transform our lives.