Linus Carl Pauling (February 28, 1901 – August 19, 1994) was an American scientist, peace activist, author and educator. He is considered the most influential chemist of the 20th century and ranks among the most important scientists in history. Pauling was one of the first scientists to work in the fields of quantum chemistry, molecular biology and orthomolecular medicine (optimum nutrition).

Pauling is one of a small group of people who have been awarded more than one Nobel prize, one of only two people to receive them in different fields (the other was Marie Curie) and the only person in that group to have been awarded each of his prizes without having to share it with another recipient.