An introductory textbook to the physics and technology used in radiation therapy that is the outgrowth of a course taught to medical residents in radiation oncology and which has been classroom tested over many years. Every effort has been made to make explanations clear and simple without oversimplifying - the book has been designed to be interesting to read as well as clinically relevant. The first half of the book contains the radiation physics necessary to understand radiation therapy. The second half of the book covers the applied physics and technology of radiation therapy. Topics include: treatment machines, beam calibration, dosimetric parameters, MU calculations, dose distributions in patients, electron beams, brachytherapy, radiation safety, quality assurance, imaging, and special modalities. Features: Comprehensive end of chapter summaries; Numerous example-problems; Full problem set for each chapter with selected answers; Clinically-realistic linac dosimetry data for practice MU calculations; ABR physician board certification physics topic matrix; ARRT exam topic matrix.