When Hans Berger was serving a year in the German military, in 1892, he was thrown from a horse. This in itself wasn't strange. But later that day, as the neurologist David Millett recounts in Perspectives in Biology and Medicine, Berger got a telegram from his father, just checking on his well being. Berger's father had never sent him a telegram before. But his older sister had just had a feeling …

For Berger, this uncanny encounter determined a lifetime of research in medicine and psychology. How did the brain—the mind—interact with the outside world? What was it that prompted his sister to worry about him that day and tell his father to check in on him? He began his work trying to understand and measure the psychic energy of the brain.

Only recently, though, have researchers really begun to understand what gives rise to uncanny feelings in the brain, and though Berger's research project began grandly, it narrowed, over decades, to a much simpler goal—he wanted to record the electrical signals of the brain. By the time he started seriously on this quest, Berger had already tried to measure blood flow and heat in the brain and correlate those changes with neurological stimuli. His work was quixotic, and in the German town where he lived, his colleagues were skeptical of his obsession.