The discovery of electroencephalography (EEG) in 1929 by the German psychiatrist Hans Berger was a historical breakthrough providing a new neurologic and psychiatric diagnostic tool at the time, especially considering the lack of all those now available in daily practice (EP, CT, MRI, DSA, etc.) whithout which the making of neurologic diagnosis and planning neurosurgical operative procedures would now be unconceivable. There are no recent reports on the topic in the Croatian medical literature. The methods used in the study included search through previous reports, bibliographic notes, Internet sources, and analysis of continuous scientific attempts made through centuries to discover the real nature and meaning of electrical activity. Galvani's accidental discovery of "biological electricity" led to Volta's discovery of the battery (voltaic pile). Using it, Rolando was the first to stimulate cerebral surface. Thus, enabling Fritsch and Hitzig and Ferrier to develop the idea of cerebral localization (Jackson, Gowers, Gotch and Horsley). It was understandable that brain electrical stimulation produces contralateral motor response, but it was unknown whether there was a spontaneous (intrinsic) brain electrical current that could be recorded. Caton was the first to report on the "current in the brain gray substances onto open brain. Based on Caton's discovery and of those of Beck, Danilevsky, Prawdicz-Neminsky and others, Berger made the first EEG (electrocorticogram) recording on July 6, 1924, during a neurosurgical operation on a 17-year-old boy, performed by the neurosurgeon Nikolai Guleke. He reported on the topic in 1929, using the terms alpha and beta waves. The "spike and waves" (Spitzenwellen) were described shortly thereafter by the American group of EEG pioneers (H. and P. Davies, F. and E. Gibbs, Lenox and Jasper), although Berger had also observed them but considered them artifacts. The discovery of electroencephalography was a milestone for the advancement of neuroscience and of neurologic and neurosurgical everyday practice, especially for patients with seizures. The real nature of the disease and its management (anticonvulsants, excision of brain scars, tumors, etc.) were unkonown at that time. Berger's persistent, hardworking and steady personal style overcame all technical and other obstacles during the experiments. Unfortunately, he gained neither acceptance nor recognition, among his fellow contemporaries from abroad. Political turmoils at the dawn of World War II, in the country of Nazi's ideology and finally the outbreak of war, along with the complete ban of any further work on EEG after his forced retirement, led him to an uneasy professional and personal end. In the era when lumbar puncture, pneumoencephalography and ventriculography were the only diagnostic tools to detect and localize "sick sites" in the brain, EEG revolutionized daily neurologic and neurosurgic procedures, and bridged a time period of about 40 years (1930-1970) until the advent of computer tomography. Nowadays its importance is not as great as it was before, but it still has its place in the diagnostic work-up of seizures, brain tumors, degenerative brain changes, and other diseases.