This book provides a first authoritative text on radiochromic film, covering the basic principles, technology advances, practical methods, and applications. It focuses on practical uses of radiochromic film in radiation dosimetry for diagnostic x-rays, brachytherapy, radiosurgery, external beam therapies (photon, electron, protons), stereotactic body radiotherapy, intensity-modulated radiotherapy, and other emerging radiation technologies. The expert authors address basic concepts, advantages, and the main applications including kilovoltage, brachytherapy, megavoltage, electron beam, proton beam, skin dose, in vivo dosimetry, postal and clinical trial dosimetry. The final chapters discuss the state of the art in microbeam, synchrotron radiation, and ultraviolet radiation dosimetry.