John Michael Ziman. 16 May 1925 — 2 January 2005

John Ziman was a theoretical physicist whose work was characterized by its clarity and simplicity and was always firmly grounded in experimental reality. He developed and refined the application of quantum mechanics to the transport properties of crystalline solids, and pioneered the quantum theory of disordered solids and liquid metals. He served as Head of the Physics Department at Bristol University, and created the theoretical physics group there. In many influential books and articles he broke fresh ground in his studies of science as a collective human enterprise.