John Darlington is a British academic, researcher and author. He is an Emeritus Professor at Imperial College London. He was Director of the London e-Science Centre and was head of the Functional Programming and Social Computing Sections at Imperial. Darlington is known for the early work he did on program transformation and functional programming. In his thesis in 1972, Darlington popularized the idea of program transformation, i.e. manipulating programs into alternative forms, preserving their semantics while altering their operational characteristics. Early life and education Darlington completed his B.Sc. (Econ) in 1969 from the London School of Economics and his Ph.D. in Artificial Intelligence from the Department of Machine Intelligence at the University of Edinburgh in 1973. He was a Research Fellow at the Edinburgh University from 1973 to 1977. Later he was a Visiting Research Fellow at IBM Yorktown Heights and the Stanford Research Institute. Career In 1977, Darlington joined Imperial College as a lecturer in the Department of Computing, becoming a Reader in 1982 and a Full Professor in 1985. At Imperial College, he held several positions as Director of Centres aimed at developing the application of parallel and novel computer architectures. These include, the Imperial College/Fujitsu Parallel Computing Research Centre (1994-2000), the Imperial College Parallel Computing Centre (1996-2002), the London e-Science Centre (2002-2005) and the Imperial College Internet Centre (2005-2008). In 2015 Darlington became an Emeritus Professor at Imperial College. He retired in 2016, aged 69. Research and work Computer science research Darlington is known for early work he did on program transformation and functional programming. In his thesis in 1972 Darlington introduced the idea of program transformation, i.e. manipulating programs into alternative forms, preserving their semantics while altering their operational characteristics In subsequent work with his supervisor, Rod Burstall, Darlington developed the unfold/fold calculus for program transformation This system of six rewrite rules has become classic and forms the basis of a great deal of work in many areas that continues to this day. From this work Burstall and Darlington introduced a novel functional language, NPL, based on Kleene Recursion Equations that made an early contribution to the development of the multi-equational, pattern matching style of pure functional programming Darlington was an early proponent of functional programming languages and the declarative approach in general. He founded and led the Functional Programming Section in the Department of Computing at Imperial College in 1977, served on IFIP Working Group