According to conventional wisdom, our unique human intellect results from evolutionary pressures for skilled tool use and for communication to enhance co-operation. This book explores a quite different idea: that the driving force was social expertise, allowing subtle manipulation of others within the social group. The need to outwit one's clever colleagues then produces an evolutionary spiralling of `Machiavellian intelligence'. This book forms a complete and self-contained text on this topic, including the origins of the idea, a wealth of exciting applications in anthropology, psychology, and zoology, and a current evaluation of more traditional ideas --to what extent is Machiavellian intelligence complementary or alternative to them? With contributions by an international team of authors, the reader is brought to the frontiers of scientific work on the origin of human intellect.