Jeffrey Huw Williams was born in Swansea, Wales, on 13 April 1956, he gained his PhD in chemical physics from Cambridge University in 1981. His career has been in the physical sciences. First, as a research scientist in the universities of Cambridge, Oxford, Harvard and Illinois, and subsequently as a physicist at the Institute Laue-Langevin, Grenoble, one of the world's leading centres for research involving neutrons and neutron scattering. He has published more than sixty technical papers and invited review articles in the peer-reviewed literature. However, he left research in 1992 and moved to the world of science publishing and the communication of science by becoming the European editor for the physical sciences for the AAAS's Science. Subsequently, he was the Assistant Executive Secretary of the International Union of Pure and Applied Chemistry, the agency responsible for the advancement of chemistry through international collaboration. Most recently, 2003–2008, he was the head of publications at the Bureau international des poids et mesures (BIPM), Sèvres. The BIPM is charged by the Metre Convention of 1875 with ensuring world-wide uniformity of measurements and their traceability to the International System of Units (SI). It was during these years at the BIPM that he became interested in, and familiar with the origin of the Metric System, its subsequent evolution into the SI, and the coming transformation into the Quantum-SI. Since retiring, he has devoted himself to writing; in 2014 he published Defining and Measuring Nature: The make of all things in the IOP Concise Physics series. This publication outlined the coming changes to the definitions of several of the base units of the SI, and the evolution of the SI into the Quantum-SI.