This book is an introduction and reference for the applications of integral transforms to a wide range of common mathematical problems. Emphasis is placed on the development of techniques and on the connection between properties of transforms and the kinds of problems for which they provide tools. Over 400 problems accompany the text, illustrating areas of applications. This third edition has been substantially updated, extended, and reorganized. Chapter one is largely new, covering introductory aspects of complex variable theory. Chapters 2-6 are devoted to the Laplace transform and include material on ordinary differential equations and partial differential equations. Chapters 7-11 cover the Fourier transform by exposition and application. Chapters 12-13 discuss techniques of the Mellin transform, and the final chapter on the numerical inversion of the Laplace transform brings up to date the enormous progress in the area. Graduate students and researchers working in mathematics and physics will find this book useful.