This chapter discusses the ways in which natural selection has acted on the animal and primate brain, demonstrating that the human brain is better at some tasks, whereas other animals are better at certain others (e.g. special memory and chimpanzees). Human brains are the results of selection for very specific tasks, largely relating to social information. It also discusses the role of metabolism in brain evolution, reviewing the ‘expensive tissue hypothesis’. It summarizes brain anatomy, and shows that, anatomically, the human brain is essentially a scaled-up primate brain. Finally, it discusses the idea of consciousness, the ways we evaluate it in other animals, and how it may have arisen.