The AOA Neurosurgery Residencies are a strong and one of the fastest growing disciplines of the American College of Osteopathic Surgeons (ACOS). The history of Medicine dates back to the first laying on of hands to comfort, and hold pressure on a bleeding wound. It has advanced through the rich history of the AOA, and ACOS, all of which have been the fabric into which has been woven Neurosurgery. The origin of AOA Neurosurgery started years ago in California. Sam Sheppard, DO completed his medical school training at Los Angeles Osteopathic School of Physicians and Surgeons and was the first DO to study neurosurgery. He completed his neurosurgery residency under Dr. Randall Chapman at the Los Angeles County Hospital in the late 1940’s to become the first AOA neurosurgeon. He was later followed by Dr. Jack Renoe, Dr. Armond Marouk and Dr. Raymond Ruberg. In 1962, when the California Osteopathic physicians decided to join the ranks of the allopathic physicians, Dr. Marouk, Dr. Renoe and Ruberg did not. Dr. Sheppard had previously moved to Ohio. Since Drs. Marouk, Renoe and Ruberg stood for osteopathy they were required to give up their license and move to another state. Dr. Marouk moved to Oklahoma, Dr. Renoe to Ohio and Dr. Ruberg moved to Pennsylvania. Other Osteopathic surgeons who were interested in neurosurgery at that time, Dr. John Ziegler, Dr. David Carr, and Dr. Quinlevan obtained their neurosurgery training from Dr. Yassargil. These six pioneering neurosurgeons, who fought the injustice, who went where no Osteopath had gone before, are our original mentors, the ones who provided guidance to their students. These students became the teachers, the ones who set the foundation for all of Osteopathic neurosurgical training. They then trained the second generations of AOA neurosurgeons. Dr. Ziegler trained Dr. Lou Jacobs. Dr. Ruberg trained Dr. Richard Kanoff. Dr. Quinlevan trained Dr. Thomas Goodall. Dr. Marouk trained Dr. Clark Okulski and Dr. Rodney Routsong. These became some of the current program directors. Others trained at that time were Dr. James Tyler, Dr. Earl Gonyaw, Dr. John McCraken and the first female AOA neurosurgeon Dr. Sally Halgren.