Today, hemispherectomy is a well-established procedure for the treatment of some sorts of catastrophic epilepsies. This, however, has not always been the case. The technique was developed to deal with brain tumors; however, the initial results were not remarkable. Moreover, when its morbidity became evident, it was almost abandoned. Had it not been for a shift in its use, with a huge increase in operations on patients with infantile hemiplegia, this surgery would certainly have disappeared. This paper focuses on the facts that surrounded these early years.