The most academically credible case for alien visitation. Is the existance of civilisation on earth the result of contact from inhabitants of a planet in the system of the star Sirius prior to 3000BC? There are tribal cultures in present-day Africa whose most sacred and secret and traditions are based on this theory. Central to their cosmology is a body of knowledge concerning the system of the star Sirius that is astounding it in its accuracy of detail, including specific information only recently accessible to modern science. Robert Temple traces the traditions of the Dogon and three related tribes back 5, 000 years to the ancient Mediterranean cultures of Sumer and Egypt. He shows a knowledge dependent on physics and astrophysics, which they claimed was imported to them by visitors from Sirius.