Abraham Pais (1918-2000) was an award-winning physicist and biographer. Gaining his PhD from Utrecht, he went on to work closely with Niels Bohr in Copenhagen before joining the Institute for Advanced Study in Princeton, and leading the Theoretical Physics Group at Rockefeller University. His work brought him into close professional, and personal, contact with the 20th century's leading physicists - Dirac, Pauli, Gell-Man, and Einstein. He retired in 1978 to write widely respected scientific biographies, and was awarded the Oppenheimer Prize in 1979.