I explore what it is that makes brains the way they are. Primates, and especially humans, have exceptionally large brains for their body size. Between primates, brains differ in size and in their internal organization. Why is this? I believe that each brain is an adaptation to the particular environment its owner lives in. I try to understand differences between brains as the result of deviations from ancestral brains that arose to deal with challenges in the environment.