In physics and especially relativity, General Relativity is a popular textbook on Einstein's theory of general relativity written by Robert Wald. It was published by the University of Chicago in 1984. The book, a tome of almost 500 pages, covers many aspects of the General Theory of Relativity. It is divided into two parts, the second of which covers more advanced topics such as causal structure, spinors and quantum effects. The book uses the −+++ sign convention (except in chapter 13) and in general the sign conventions used in the textbook Gravitation (book). The book uses the Abstract index notation for tensors.