Witness: Witness Archive 2015

On 10 April 1964, the famously eccentric concert pianist Glenn Gould retired from live performance at the age of 31. One of the most celebrated pianists of the 20th Century, Gould was a reclusive figure celebrated for his unusual interpretations - and also his habit of humming along with his own performances. John Roberts was one of his friends. (Photo: Canadian pianist-composer Glenn Gould rehearsing with an orchestra at the Royal Festival Hall, London for a series of Beethoven concertos, using a piano stool only a few inches from the floor. Credit: Keystone/Getty Images)