Arjun Sahgal, MD (chief editor), is a leader in the field of high-precision stereotactic radiation to the brain and spine. After training at the University of Toronto, Ontario, Canada, in radiation oncology, he completed a fellowship at the University of California, San Francisco, in brain and spine radiosurgery with Dr. David Larson. Since then he has been recognized as a national and international clinical expert and research leader in radiosurgery. His main focus is on developing spine stereotactic body radiotherapy as an effective therapy for patients with spinal tumors. He has published numerous book chapters on the subject and more than 200 peer-reviewed papers in high-impact journals, including Journal of Clinical Oncology and The Lancet Oncology. He has edited or written several books specific to research on brain and bone metastases and is an editorial board member for several journals. He was chairman of the International Stereotactic Radiosurgery Society meeting (June 2013) and was a board member for the Brain Tumour Foundation of Canada and the International Stereotactic Radiosurgery Society. He has been invited to speak at several international meetings, has been a visiting professor at various universities, and leads several research groups. His further research activities involve integrating MRI into radiotherapy delivery, combining novel pharmacologic therapies with radiosurgery, and MRI-guided focused ultrasound.