Development of posterior fossa surgery remains Harvey Cushing's hallmark contribution to pediatric neurosurgery. During the era before Cushing, posterior fossa lesions were considered inoperable, and only osseous decompressive surgery was offered. The evolution of Cushing's surgical expertise from subtemporal decompressions to total extirpation of vascular fourth ventricular tumors, combined with a dramatic decrease in his operative mortality rate, reflects the maturation of modern neurosurgical techniques. A comprehensive review of the medical records of Cushing's pediatric patients treated between 1912 and 1932 revealed that procedures such as lateral ventricular puncture (to decrease cerebellar herniation), transvermian approach to midline tumors, and electrocoagulation were the key factors punctuating the path to his pioneering achievements in posterior fossa surgery. The outcome of such operations was improved by his recognition of the importance of tumor mural nodule in cyst recurrence, as well as elucidation of the histogenesis of pediatric posterior fossa tumors to tailor treatment including radiotherapy.