Nine years after the publication of Comets and the Origin and Evolution of Life, one of the pioneering books in Astrobiology, this second edition revisits the role comets may have played in the origins and evolution of life. Recent analyses of Antarctic micrometeorites and ancient rocks in Australia and South Africa, the continuing progress in discovering complex organic macromolecules in comets, protostars and interstellar clouds, new insights into organic synthesis in comets, and numerical simulations of comet impacts on the Earth and other members of the solar system yield a spectacular wealth of new results. This second edition is thus actually a new book. As the first edition it is intended as a comprehensive review of current research, accessible to graduate students and others new to the field. Each chapter was prepared by experts to give an overview of an aspect of the field, and carefully revised by the editors for uniformity in style and presentation.