IN daily life there is found an abundance of actions performed by people which makes it necessary to posit some underlying mechanism in order to account for them. One man stays at home and builds up· a vast collection of British Colonial stamps, another travels to the Himalayas and ascends a hitherto unconquered peak. Schliemann from a very early age had the ambition to discover the ancient site of Troy; Amundsen longed to be a polar explorer since adolescence. While some people have relatively simple desires such as the satisfaction of bodily impulses, others are compelled by a dynamic restlessness to break the world record in pole-squatting. In short, different people have different wants and they perform various actions in order to satisfy them. The study of these different wants is the study of motivation.