Born in 1918 in Cardiff, Wales, the son of Eli and Molly Reuben, practising Orthodox Jews of Latvian origin,[1][2] Harold was the eldest of four siblings, all of whom were musical.
By the age of 10, he was winning piano prizes and performing with, for example, the Scottish Symphony Orchestra under George Szell.
[3] At the age of seven having, according to his sister Bernice Rubens, "exhausted all the local teachers", Harold began travelling to London to study with Madame Maria Levinskaya.
While teaching at the South African College of Music in Cape Town, he was the first musician to refuse to play to segregated audiences;[2] during the ANC Treason Trial (1956–1961) he played high-profile concerts to raise money for ANC defendants; and his home in Newlands became a meeting place for other movement members, including Nelson Mandela and Albie Sachs, who recalled:[1][5] We were meeting in the underground in their cottage in Newlands.
We would hear him practising the fourth Beethoven piano concerto, going over it and over and over again while we were doing our secret planning in the room next door.