USA scientist Linus Pauling won two Nobel Prizes, one in Chemistry and the other in what category?

Linus Carl Pauling, (born February 28, 1901, Portland, Oregon, U.S.—died August 19, 1994, Big Sur, California), was a theoretical physical chemist who became the only person to have won two unshared Nobel Prizes. His first prize (1954) was awarded for research into the nature of the chemical bond and its use in elucidating molecular structure; the second (1962) recognized his efforts to ban the testing of nuclear weapons. After his early education in Condon and Portland, Oregon, he attended Oregon Agricultural College (now Oregon State University), where he met Ava Helen Miller, who would later become his wife, and where he received his Bachelor of Science degree in chemical engineering "summa cum laude" in 1922.

During the 1950s Pauling and his wife became well known to the public through their crusade to stop the atmospheric testing of nuclear weapons. In 1958 they presented an appeal for a test ban to the United Nations in the form of a document signed by 9,235 scientists from 44 countries. Pauling’s sentiments were also promulgated through his book "No More War! "(1958), passionate analysis of the implications of nuclear war for humanity. In 1960 he was called upon to defend his actions before a congressional subcommittee. His work on behalf of world peace was recognized with the 1962 Nobel Prize for Peace awarded on October 10, 1963, the date that the Nuclear Test Ban Treaty went into effect.