Lars Onsager was a Norwegian-born American physical chemist and theoretical physicist. Lars Onsager was born in Oslo, Norway on November 27, 1903. His early work in statistical mechanics attracted the attention of the Dutch chemist Peter Debye, under whose direction Onsager studied at the Federal Institute of Technology, Zürich (1926–28). He then went to the United States and taught at Johns Hopkins University, Baltimore, and Brown University, Providence, R.I. He received his Ph.D. from Yale University in 1935. He had joined the faculty of Yale in 1933 and became professor of theoretical chemistry there in 1945. In 1968, he received the National Medal Of Science.

Onsager is a Fellow of the American Physical Society and The New York Academy of Sciences, a member of The American Chemical Society, The Connecticut Academy of Arts and Sciences, The National Academy of Sciences, The American Academy of Arts and Sciences and The American Philosophical Society, a Foreign Member of the Norwegian Academy of Sciences, The Royal Norwegian Academy of Sciences, The Norwegian Academy of Technical Sciences, the Royal Swedish Academy of Sciences and The Royal Science Society in Uppsala, and an Honorary Member of The Norwegian Chemical Society.