The aim of the International Stereotactic Radiosurgery Society (ISRS) is to promote technical developments in stereotactic radiosurgery on the highest level of clinical experience based on clinical investigations. In this volume, high-quality peer-reviewed papers from the 8th International Stereotactic Radiosurgery Society meeting held in San Francisco 2007 are presented. The reports include new studies on physics, imaging and radiobiology in radiosurgery as well as the latest research in the field of cranial radiosurgery on benign tumors, malignant tumors and vascular malformations. Further articles cover new investigations in the practice on spinal and body radiosurgery. This publication is of special interest to neurosurgeons, radiation oncologists and medical physicists who require precise information to keep up to date with the important developments on the use of stereotactic radiosurgery.