The idea that comets may be connected with the origins of life on Earth was considered heresy decades ago, but is now slowly gaining respect and support. The recent surge of interest in astrobiology has led to a spate of books designed for university courses, but the subject of cometary panspermia is only dealt with very briefly. Future space missions are directed to verifying aspects of this subject, and this definitive book by one of the pioneers of the field makes essential reading. The book presents the growing case for cometary panspermia in a cogent form, citing evidence from space science, geology and biology. It forms an important component of any undergraduate course on astrobiology, whilst also serving the needs of researchers in the field.