Harry Messel AC CBE (1922-2015), scientist and academic, was born in Canada and gained his qualifications there and in Scotland and Ireland. He came to Australia after the war, and taught for two years at Adelaide University. In 1952, aged just 29, he was appointed to the University of Sydney as Professor and Head of the School of Physics. Over the unprecedented 35 years that Messel ran the School it developed into one of the world's leading university physics departments. To support its research Messel established the first university foundation in the British Commonwealth, the Nuclear Research Foundation, through which he raised enormous sums. A high-profile intellectual, he advised on government policy, pioneered the introduction of computers in Australia, contributed substantially to high school science education through his widely-used science textbook and encouraged students to pursue careers in science through his International Science Schools. After his retirement from the university in 1987 Messel served on the World Conservation Union, heading its Crocodile Specialist Group from 1989 to 2004. He served on the Australian Atomic Energy Commission from 1975 to 1981, and was Chancellor of Bond University from 1992 to 1997.