Bernd Theodor Matthias (8.06.1918-27.10.1980) was an American physicist and a member of the National Academy of Sciences (1965). He was born in Frankfurt am Main (Germany). He graduated from the Zurich Polytechnic, where he worked in 1942—47. In 1947 he moved to the USA, where from 1948 he worked at the Bell Telephone laboratories and from 1961 was professor at the University of California at San Diego (from 1971 — also director of the Institute for Pure and Applied Physical Sciences). His research concerned solid-state physics, magnetism, low-temperature physics, superconductivity and the physics of materials. He constructed (1948) a microscopic theory of ferroelectricity. He established that a certain type of structure favours the appearance of superconductivity, and he found experimentally that the critical temperature of superconductors is very sensitive to the presence of paramagnetic impurities. He discovered a number of new families of ferroelectrics and created a considerable number of new materials, among them superconductors with a high critical temperature. In particular, in 1961 he created materials based on Nb3Sn with a strong field and a high current density, which led to a new technology for producing superconducting magnets. He studied the relation between superconductivity and magnetic order in solids and pointed out a number of regularities characteristic of superconductivity. In 1958 he obtained a ferromagnetic superconductor. He founded a school of physicists.