Born into a farming family, John Harper identified a number of influential figures in his formal education, including his inspirational school master Wilfred Kings, and the plant ecologists Roy Clapham (FRS 1959) and Jack Harley (FRS 1964) and animal ecologists Charles Elton (FRS 1953) and George Varley during his university education at Magdalen College, Oxford. His first academic appointments were in the University of Oxford School of Rural Economy and the Department of Agriculture, where he carried out pioneering research on seed and seedling mortality and the ecology and control of weeds. In 1960 John was appointed to head the Department of Agricultural Botany at the University College of North Wales, Bangor. The departments of Botany and Agricultural Botany merged in 1967 with John as head of the new School of Plant Biology. From this base, he established a research centre that attracted students and visitors from around the world. As one of the most influential of thinkers, John Harper generated a new discipline: plant population biology. In addition, by integrating advances in animal population biology and evolution into his own work, John helped to create a complete master discipline of ecology, as reflected in a textbookEcology: individuals, populations and communities(Oxford, UK: Blackwell) for which he received (with co-authors Mike Begon and Colin Townsend) an exceptional lifetime achievement award from the British Ecological Society.