Dennis William Siahou Sciama, FRS (/ʃiˈæmə/; 18 November 1926 – 18/19 December 1999) was a British physicist who, through his own work and that of his students, played a major role in developing British physics after the Second World War. He was the PhD supervisor to many famous cosmologists, including Stephen Hawking, Martin Rees and David Deutsch; he is considered one of the fathers of modern cosmology.