First published in 1979 as the second edition of a 1972 original, this textbook provides a systematic account of an important area of organic chemistry - that of cycloadditions and molecular rearrangements. The necessary theoretical background for understanding these reactions is presented in non-mathematical form and various alternative approaches to the theory are compared. The core of the book is a descriptive account of various types of cycloaddition and rearrangement reactions. The synthetic importance of these reactions is emphasised and, by providing the mechanistic background, the book demonstrates to the reader the relationship between the different types of reactions. This book will be of value to anyone with an interest in organic chemistry.