Radiation dosimetry has made great progress in the last decade, mainly because radiation therapy is more widely used. Every medium to large sized hospital has an oncology department with at least one, generally more, linear accelerators for tumor treatment. Radiation dosimetry has become a common need in the medical world. Medical physicist is now a certified profession and is required by the law in every hospital where radiation treatment is given to patients. One of the main tasks of the medical physicist is to provide the physician with an accurate measurement of the dose delivered to the patient. Several measurement methods were developed together with improved calculation methods, correction factors, and Monte Carlo simulation. It was the intention of the author to assemble this past decade’s developments in one short volume. Unfortunately, because of the vast amount of material, only selected information could be included, and many important developments in this field had to be left out.