This well-received book, now in its fifth edition, is unique in providing a detailed examination of the technological basis of radiation therapy. Another unique feature is that the chapters are jointly written by North American and European authors. This considerably broadens the book’s contents and increases its applicability in daily practice throughout the world. The book is divided into two sections. The first section covers basic concepts in treatment planning and explains the various approaches to radiation therapy, such as intensity-modulated radiation therapy, tomotherapy, stereotactic radiotherapy, and high and low dose rate brachytherapy. The second discusses in depth the practical clinical applications of the different radiation therapy techniques in a wide range of cancer sites. All chapters have been written by leaders in the field. This book will serve to instruct and acquaint teachers, students, and practitioners with the basic technological factors and approaches in radiation therapy.