Born 28 Feb, 1901: Linus Pauling was a pioneering American chemist, biochemist, and peace activist, renowned for his groundbreaking work across several scientific disciplines. He is notably recognized for his research in the nature of the chemical bond, leading to the development of the concept of orbital hybridization and the introduction of the Pauling scale for electronegativity. Pauling's work laid the foundational principles for quantum chemistry and molecular biology. He was also pivotal in identifying the alpha helix and beta sheet structures of proteins. Beyond his scientific achievements, Pauling was a vocal advocate for nuclear disarmament, earning him the Nobel Prize in Chemistry in 1954 for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances, and the Nobel Peace Prize in 1962 for his efforts against nuclear weapons testing, making him the only person to receive two unshared Nobel Prizes.