The aquatic ape hypothesis (AAH), also referred to as aquatic ape theory (AAT) or the waterside hypothesis of human evolution, postulates that the ancestors of modern humans took a divergent evolutionary pathway from the other great apes by becoming adapted to a more aquatic habitat. While the hypothesis has some popularity with the lay public, it is generally ignored or classified as pseudoscience by anthropologists.

Sir Alister Clavering Hardy was an English marine biologist, an expert on marine ecosystems spanning organisms from zooplankton to whales. He had the artistic skill to illustrate his books with his own drawings, maps, diagrams, and paintings.