Sir David John Cameron MacKay (22 April 1967 – 14 April 2016) was a British physicist, mathematician, and academic. He was the Regius Professor of Engineering in the Department of Engineering at the University of Cambridge and from 2009 to 2014 was Chief Scientific Advisor to the UK Department of Energy and Climate Change (DECC). MacKay wrote the book Sustainable Energy – Without the Hot Air. Education MacKay was educated at Newcastle High School and represented Britain in the International Physics Olympiad in Yugoslavia in 1985, receiving the first prize for experimental work. He continued his education at Trinity College, Cambridge, and received a Bachelor of Arts degree in Natural Sciences (Experimental and theoretical physics) in 1988. He went to the California Institute of Technology (Caltech) as a Fulbright Scholar, where his supervisor was John Hopfield. He was awarded a PhD in 1992. Career and research In January 1992 MacKay was appointed the Royal Society Smithson Research Fellow at Darwin College, Cambridge, continuing his cross-disciplinary research in the Cavendish Laboratory, the Department of Physics of the University of Cambridge. In 1995 he was made a University Lecturer in the Cavendish Laboratory. He was promoted in 1999 to a Readership, in 2003 to a Professorship in Natural Philosophy and in 2013 to the post of Regius Professorship of Engineering. MacKay's contributions in machine learning and information theory include the development of Bayesian methods for neural networks, the rediscovery (with Radford M. Neal) of low-density parity-check codes, and the invention of Dasher, a software application for communication especially popular with those who cannot use a traditional keyboard. He cofounded the knowledge management company Transversal. In 2003, his book Information Theory, Inference, and Learning Algorithms was published. His interests beyond research included the development of effective teaching methods and African development; he taught regularly at the African Institute for Mathematical Sciences in Cape Town from its foundation in 2003 to 2006. In 2008 he completed a book on energy consumption and energy production without fossil fuels called Sustainable Energy – Without the Hot Air. MacKay used £10,000 of his own money to publish the book, and the initial print run of 5,000 sold within days. The book received praise from The Economist, The Guardian, and Bill Gates, who called it "one of the best books on energy that has been written." Like his textbook on Information theory, MacKay made the book available for