This publication aims to give comprehensive information on the methods of gamma knife radiosurgery and the results of treatment of the most frequent diagnoses using radiosurgery. A summarisation of existing knowledge and results obtained in gamma knife radiosurgery world-wide is based on experience with treatment of more than 13,500 patients over 20 years at Na Homolce Hospital, Prague. Besides detailing the basic data of Leksell gamma knife radiosurgery, this book also provides thorough technical description of former and existing gamma knife models, basic physics principles of gamma knife radiosurgery, calibration and quality assurance as well as standardised treatment procedures. The book is primarily intended for physicians, who, together with the patient decide on the most appropriate methods of treatment for each diagnosis. The publication can be also helpful to medical physicists who are involved in gamma knife radiosurgery and responsible for its calibration and quality assurance. Finally, it is also intended for patients who are looking for, if necessary, more comprehensive information on the radiosurgical treatment method for tumours and other brain disorders.