This book delves into one of the greatest riddles perplexing modern science: Why are humans so smart? In a format understandable even by the non-expert, the author investigates the origins of human intelligence, starting with classical Darwinian concepts. Thus, the strengths and beauty of natural selection are presented with many examples taken from natural history. Common criticisms of Darwin, from scientists and non-scientists alike, are confronted and shown to be either inconclusive or outright false. The author then launches into a discussion of human intelligence, the most important feature of human evolution, and how it cannot be fully explained by mutational selection.Modern humans are smarter than what is demanded by our evolutionary experience as hunter-gatherers. The difficulty lies in the inability of natural selection to answer the following question: how can a complex set of genes, controlling expensive traits with little immediate benefit, come into permanent existence within a short time period in every member of a small population (which was dispersed and geographically isolated over a huge planet) which had a low reproductive output and a low mutation rate? The book concludes with a speculative epigenetic theory of intelligence that does not require DNA mutations as a source of evolution.