John Meurig Thomas is a former Director of the Royal Institution of Great Britain, a former head of the Department of Physical Chemistry and former Master of Peterhouse, University of Cambridge. A world-renowned solid-state, materials and surface chemist, he has been an educator, researcher, academic administrator, author of university texts, government advisor, industrial consultant and trustee of national museums in a career spanning over 50 years. Recipient of many international awards, including the Linus Pauling, Willard-Gibbs, Kapitza, Natta, Stokes, Davy and Faraday medals, he is also a fellow of the Royal Society (1977), of the American Philosophical Society (1993) and of ten other national academies. He is best known for his fundamental work in heterogeneous catalysis, chemical electron microscopy and in the popularisation of science, for which, in conjunction with his services to chemistry, he was knighted (1991). He is also founding editor of three scientific journals and editor or co-editor of some 30 monographs. A new mineral, meurigite, was named in his honour (1995). Most recently in 2016, Sir John was awarded the Royal Medal for Physical Sciences by the Royal Society.Drawn from over 1200 publications, this volume contains a summarised account of Sir John's work, with a selection of the new techniques pioneered and discovered by him and his colleagues. Also included are popular science articles, and various illustrations of techniques which have enhanced our knowledge of many facets of condensed matter science. Contributions from 80 peers, colleagues, former co-workers, students and friends worldwide who have interacted with or been influenced by him are a tribute to the professional and personal life of Sir John, making this book a unique reflective summary of the work of one of the greatest achievers in modern British physical science.