Stereotactic radiosurgery is the least invasive of modern treatment modalities and has recently become the basic management tool in neurosurgery. Arteriovenous malformations, benign brain tumors and brain metastases are the most common indications for its use. Also, gamma knife radiosurgery is increasingly being applied to extracranial pathologies, e.g. tumors of the spine and cancers of the lung, liver, pancreas and prostate. Approximately one quarter of patients undergoing gamma knife radiosurgery worldwide are treated in Japan. This publication provides an excellent overview of Japan's 20-year experience with stereotactic radiosurgery using the Leksell Gamma Knife. Leading experts discuss their long-term results with gamma knife radiosurgery. Studies focusing on dose selection for optimal treatment results and avoidance of complications are also presented. In addition, gamma knife treatments of extracranial pathologies are reviewed. Neurosurgeons, neurologists, oncologists and workers in radiology and cardiology will find accurate knowledge on gamma knife radiosurgery which will be helpful with patient selection, treatment planning and delivery, and postoperative management.