We all have a natural interest in our own origins and, by extension, the origins of the world in which we live. In this volume, the first in The Darwin College Lectures Series, a distinguished team of international authorities reports on the latest research on the origins of the most fundamental features of our world. Martin Rees begins the book with a bang, the Big Bang that was the probable start of our expanding universe. The contributors then focus on the origins of the solar system, material complexity and the human species. The volume ends with essays by John Maynard Smith on Social behaviour, Ernest Gellner on society and John Lyons on language. The book derives from a highly successful series of lively public lectures which have since been revised and illustrated for publication under the editorship of Professor A. C. Fabian of the Institute of Astronomy, University of Cambridge.