Stereotactic Radiosurgery (SRS) is a technique for treating lesions, typically intracranial, most often with a single high dose of ionizing radiation which is enabled by use of a stereotactic device(s) for accurate target localization and patient immobilization. Very rapid fall off of dose to spare normal tissue is achieved by either use of multiple beams, directions, collimation, and/or by exploiting other radiation beam characteristics. While the roots of SRS are often traced back to 1951 and the Swedish Neurosurgeon, Dr. Lars Lekskell, it is only recently that ?the state of the art? of SRS has experienced its greatest change. Clearly much of this change can be attributed to the very nature of technological evolution witnessed in the areas of computer and/or imaging sciences. However, much can also be attributed to the increased and practical availability of this technology in its various forms (e.g., gamma knife and/or linear accelerator based) with the associated increase in dedicated investigators evaluating, revolutionizing, and defining use of this technology. The very nature of SRS calls for collaboration amongst multiple specialists and/or researchers inclusive of Radiation Oncologists, Medical Physicists, Radiobiologists, Radiologists, Neuro-Oncologists, and Neurosurgeons. Such multi-disciplinary integration can only foster continued evolution, research, and growth within a discipline and is reflected in this issue dedicated to SRS.