Our breathtaking intelligence is embodied in our skills. Think of Olympic gymnastics, and the amount of strength and control required to perform even a simple beam routine; think of a carpenter skillfully carving the wood, where complicated techniques come across as sheer easiness of the bodily movements; of a pianist performing a sonata, balancing technical virtuosity with elegance. Throughout our lifetimes, we acquire and refine a vast number of skills, and the improvement and refinement of skills are not bound to the human lifespan alone either: somehow, they also cross generations. Skills both foster cultural evolution and are refined by it – for example, in the way cultural evolution perfects tools and building techniques. What makes skills possible? And how can skills explain our successes? This book is the first systematic discussion of skills: of their nature, and of their relation to knowledge and reasoning.