English: Walter Dandy was neurosurgeon and scientist. Dandy was an important inventor, innovator and disseminator of hundreds of new and effective practices in neurosurgery, despite death at a young and productive age, contributed in an intense and definitive way to modern neurosurgery. Creator of pneumoventriculography, pediatric intensive care, Dandy Walker syndrome, clipping for aneurysms and craniotomy methods. First neurosurgeon considered a true scientist since he defended, used, created and disseminated the concepts of evidence-based medicine and scientific methods of Popper, mainly the essential possibility of inrefutability and importance of falsifiability in all types of researches.