Isidor Rabi

Born into an Orthodox Jewish family that emigrated from Galicia to New York's Lower East Side when he was an infant, Rabi rose from a poor immigrant childhood to lead American physics at Columbia University. He devised the molecular-beam magnetic-resonance method, which let him measure the magnetic properties of atomic nuclei with unprecedented precision. This work, honored with the 1944 Nobel Prize in Physics, became the direct foundation of nuclear magnetic resonance (NMR) and later of MRI medical imaging.