John Hasbrouck Van Vleck was an American physicist and mathematician, co-awarded the 1977 Nobel Prize in Physics, for his contributions to the understanding of the behavior of electrons in magnetic solids. He was born on March 13, 1899 in Middletown, Connecticut, United States. He earned his bachelor's degree from the University of Wisconsin in 1920. He earned his master's degree at Harvard University in 1921 and a doctorate in 1922 also at Harvard. In 1966, he received the National Medal Of Science. Van Vleck developed during the early 1930s the first fully articulated quantum mechanical theory of magnetism. Later he was a chief architect of the ligand field theory of molecular bonding. He contributed also to studies of the spectra of free molecules, of paramagnetic relaxation, and other topics. His publications include Quantum Principles and Line Spectra (1926) and The Theory of Electric and Magnetic Susceptibilities (1932). He died on October 27, 1980 in Cambridge, Massachusetts, United States.