Between 1956 and 1966, Calder wrote for the magazine "New Scientist", serving as editor from 1962 until 1966. After that, he worked as an independent author and TV screenwriter. He conceived and scripted thirteen major documentaries and series concerning popular science subjects broadcast by the BBC and Channel 4 (London), with accompanying books. For his television work he received the Kalinga Prize for the Popularization of Science during 1972. During 2004, his book "Magic Universe" was shortlisted for The Aventis Prizes for Science Books.