Herbert Henri Jasper dedicated his life to studies of the brain in relation to the mind and behavior. He pioneered the application of the electroencephalogram (EEG) for the study of the electrical activity of the brain and used this technique in studies of consciousness, learning and particularly the examination of epileptic discharge. He utilized microelectrode recordings from single brain cells and combined this technique with microchemical analyses to study cortical and sub-cortical activity. He added substantially to our understanding of brainstem and thalamic reticular formations in conditions of consciousness and in relation to petit-mal epilepsy. His work with Wilder Penfield and associates over a quarter century elucidated the mechanisms of epilepsy and added to our understanding of the functional anatomy of the human brain. An enthusiastic and able organizer, Herbert Jasper was responsible for many international conferences on brain science and worked tirelessly to develop international collaboration among investigators of the nervous system, being one of the founders of the International Brain Research Organization and the Society for Neuroscience. His prodigious contributions in basic and clinical research will be recognized by the world community of brain science for years to come.