Békésy's scientific work is assessed, after presentation of a brief biographical sketch. Emphasis is less on his actual achievements (with which the reader is presumed to be generally familiar), and more on his approaches to given problems and the unique solutions he found for many of them. Békésy was the first to study the function of the auditory organ experimentally, replacing theoretical considerations by empirical evidence. He devised novel experimental methods that were suitable for specific problems, often following up on them by an entirely different approach if the latter was more promising for the particular state of his investigation. He was an extremely keen observer, paying attention to seemingly trivial details that often formed starting points of new studies. When he occasionally became bogged down by what appeared to be insurmountable experimental difficulties, he shelved his subject temporarily, often for many years, simply to take it up again when he had found a new approach. It was only to be expected that some of his findings are now being corrected or modified. However, these new studies are conducted many decades after his original observations and measurements, and do not detract from his pioneering and towering achievements.