Walter Kohn was an Austrian-born American theoretical chemist, best known for his work in the field of quantum mechanics and computational chemistry. He was awarded the Nobel Prize in Chemistry in 1998 for developing the density functional theory, which revolutionized the way scientists understand the electronic structure of atoms and molecules. Kohn was born on March 9, 1923, in Vienna, Austria, and later emigrated to the United States in 1939. He spent much of his academic career at the University of California, Santa Barbara, where he contributed significantly to both research and education in chemistry and physics until his passing on April 19, 2023.