Short answers, pulled from the story.
Linus Pauling won two Nobel Prizes: the Nobel Prize in Chemistry in 1954 and the Nobel Peace Prize in 1962. He is the only person to have been awarded two unshared Nobel Prizes, and one of only five people in history to have won more than one Nobel Prize.
Pauling received the 1954 Nobel Prize in Chemistry for his research into the nature of the chemical bond and its application to understanding the structure of complex substances. His work introduced concepts such as orbital hybridization, electronegativity, and resonance, which remain part of standard chemistry education.
Pauling received the Nobel Peace Prize for 1962, awarded on the 10th of October, 1963, the day the Partial Test Ban Treaty went into force. The Nobel Committee cited his campaigning since 1946 against nuclear weapons tests, the spread of nuclear arms, and warfare as a means of resolving international conflicts. He had also organized a petition signed by 11,021 scientists from fifty countries calling for an end to nuclear testing.
Pauling proposed an incorrect triple-helix model for DNA that contained basic errors, including neutral phosphate groups that conflicted with DNA's known acidity. He later called missing the DNA structure the biggest disappointment of his life. His earlier work on the alpha helix and beta sheet in protein structure directly inspired James Watson and Francis Crick, who proposed the correct double helix early in 1953.
In November 1949, Pauling and his colleagues Harvey Itano, S. J. Singer, and Ibert Wells published proof that sickle cell anemia is caused by an abnormal form of hemoglobin, making it the first disease understood at the molecular level. The paper, titled "Sickle Cell Anemia, a Molecular Disease," also demonstrated for the first time that Mendelian inheritance determines the specific physical properties of proteins.
Pauling became a strong advocate for high-dose vitamin C after biochemist Irwin Stone introduced him to the idea in 1966. He published Vitamin C and the Common Cold in 1970 and collaborated with British cancer surgeon Ewan Cameron on studies of vitamin C as a cancer therapy. Clinical trials at the Mayo Clinic later found high-dose vitamin C no better than placebo for cancer, a conclusion Pauling disputed until his death in 1994.