"Origin of the Earth" is an outgrowth of the Lunar and Planetary Institute Conference on the Origin of the Earth, which was held in Berkeley, California, in December 1988, with leading earth and planetary scientists participating. Among the topics covered are theoretical models of the solar nebula, planetary accretion and models of the differentiation of the Earth into the familiar regimes of hydrosphere, crust, mantle and core. A central theme of the book is a discussion of the "giant impact" model for the formation of the Moon. This popular model of lunar origin has severe implications for the early history of the Earth. Contributors discuss whether the "giant impact" model is incorrect in relation to the Earth, or whether natural processes conspired to erase all traces of its consequences. These and other issues related to the Earth's origin and early differentiation are covered.