David MacKay was a Professor in the Department of Physics at the University of Cambridge, a Fellow of the Royal Society (FRS) and Regius Professor of Engineering at Cambridge University. He studied Natural Sciences at Cambridge and then obtained his PhD in Computation and Neural Systems at Caltech - the California Institute of Technology. He returned to Cambridge as a Royal Society research fellow at Darwin College. He is internationally known for his research in machine learning, information theory, and communication systems, including the invention of Dasher, a software interface that enables efficient communication in any language with any muscle. He taught Physics in Cambridge and devoted much of his time to public teaching about energy. He was a member of the World Economic Forum Global Agenda Council on Climate Change. From 2009 to 2014 he was Chief Scientific Advisor to the UK Department of Energy and Climate Change ("DECC") and in the 2016 New Year's Honours List was awarded a knighthood for services to Scientific Advice in Government and Science Outreach. He passed away in 2016 at the age of 48.