The popularity of Stephen Hawking's work has put cosmology back in the public eye. The question of how the universe began, and why it hangs together, still puzzles scientists. Their puzzlement began 2500 years ago when Greek philosophers first "looked up at the sky and formed a theory of everything". Though their solutions are little credited today, the questions remain fresh. The early Greek thinkers struggled to come to terms with and explain the totality of their surroundings; to identitify an original substance from which the universe was compounded; and to reconcile the presence of balance and proportion with the apparent disorder of the universe. Rosemary Wright examines the cosmological theories of the "natural philosophers" from Thales, Anaximander and Anaximenes to Plato, the Stoics and the NeoPlatonists. The importance of Babylonian and Egyptian forerunners is emphasized. This is an introduction to the cosmological thought of antiquity.