Since the beginning of civilization, the origins of the Earth and Moon have been the subjects of continuing interest, speculation, and enquiry. These are also among the most challenging of all scientific problems. They are, perhaps to a unique degree, interdisciplinary, having attracted the attention of philosophers, astronomers, mathematicians, geologists, chemists, and physicists. A large and diverse literature has developed, far beyond the capacity of individuals to assimilate adequately. Consequently, most of those who attempt to present review-syntheses in the area tend to reflect the...