This book was first published in 1982. It consists of selected contributions presented at the Nuffield Quantum Gravity Workshop held at Imperial College, London, in August 1981. The book is divided into three parts which correspond with the three separate themes pursued at the workshop. Part I is concerned with the geometrical and topological aspects of quantum gravity. Part II focuses on supergravity and its application to the Grand Unified Theories of elementary particles. Part III concentrates on the early universe and cosmology. The book, therefore, covers not only supergravity, but the whole spectrum of quantum gravity research.