In a recent study of surgical services in the United States, by the American College of Surgeons and the American Surgical Association, the application of microsurgery to the treatment of intracranial tumors and cerebrovascular disease was ranked among the first order research advances in surgery during the last 25 years. Our previous studies of microsurgical anatomy have helped to meet the need for detailed anatomic studies created by the rapid growth of microneurosurgery (clinical neurosurgery done using 2 to 40 X magnification). Multiple studies of the sella turcica, cranial base, major intracranial arteries, intracranial veins, cerebral ventricles and the cranial nerves have been completed. A major emphasis during the next year will be on studies of the intracranial arteries and the ventricular system. Surgeons from around the world tell us that knowledge gained from our studies are increasing the accuracy of their surgery.