Nobel Prize winning American physicist who was awarded the prize in 1944 for his invention of the atomic and molecular beam magnetic resonance method of observing atomic spectra.

During WWII, Rabi was a leader of the group of scientists at MIT which aided the development of radar. He was instrumental in the creation of both CERN and the Brookhaven National Laboratory. He also built up the physics department at Columbia University, one which was to produce several Nobel Prize winning physicists.

Upon the discovery of the muon, he is reported to have remarked "Who ordered that?", because the new particle didn't seem to have any purpose in the scheme of things. It was seen later on how the muon fit into a second generation of particles, across from the electron.