Frank Schmitt has for two thirds of a century been searching for -- and in many cases finding -- explanations of major biomedical importance. His is a very human story -- of a youth in high school doing experiments in a make-shift chemical laboratory in the attic of the family home; of a young university student who organized a students' science society and whose undergraduate research on cell structure was published in major professional journals; of a medical school student who wrote a thesis that attracted the attention of cardiologists for many years; of a devoted husband who, with his young wife, spent two postdoctoral years in Berkeley, London and Berlin and later made two trips around the world with her as he set up a worldwide network of neuroscientists. As a young scientist at Washington University, Schmitt investigated polarization optical and x-ray diffraction methods to discover the molecular structure of living tissues -- this, long before molecular biology was established as a scientific discipline. Schmitt was called to head biology at MIT in 1941. There he added electron microscopy to his ultrastructural repertoire and used much of it in wartime research. As an Institute Professor (MIT's highest rank), he became a leader in the founding and characterization of the fields of biophysic and neuroscience. Schmitt was also deeply committed to music, along with his wife, and had an interest in theology. Photos.