John David Barrow. 29 November 1952—26 September 2020

John Barrow wrote dozens of books and hundreds of papers, including more than 10 papers and one book during his final illness, addressing a grand problem: why is the universe the way it is? What is the fundamental nature of physics, and what are its cosmological outcomes? His most famous book was on the Anthropic Principle with Frank Tipler, and his most significant physics research was on the possibility of a variation of the fundamental constants of physics—which, if true, requires a rejigging of our foundational physics theories. He was an outstanding communicator of science to the public, being asked to lecturer at as varied places as Downing Street and Buckingham Palace. His most important public service was as director of the Millennium Mathematics Project, for which he was awarded the Queen's Anniversary Prize for Educational Achievement by Queen Elizabeth II at Buckingham Palace. He was awarded many other prizes, including the Templeton Prize, the Gold Medal of the Royal Astronomical Society, both the Kelvin Medal and the Dirac Gold Medal of the Institute of Physics and the Faraday Medal of the Royal Society.