Dr. Leon Rosenfeld has now taken up the position, to which he was recently appointed, of professor of theoretical physics in the University of Manchester in succession to Prof. D. R. Hartree. Prof. Rosenfeld was born in 1904 in Liège, graduating there in 1926. He then spent a year in Paris at the École Normale Superieure, during which he worked with Prof. Louis de Broglie. His first published work, on five-dimensional relativity, appeared about this time. In 1927 he went as assistant to Prof. Max Born in Göttingen, and while there worked on problems of optical activity and the Faraday effect; then to Zurich with Prof. Pauli, where he studied quantum electrodynamics. In 1931 he became a teacher in the School of Electrical Engineering at Liège. From 1930 until 1940 he worked in very close collaboration with Prof. Niels Bohr, spending a considerable part of each year in Copenhagen. In 1935 he was elected to the chair of theoretical physics at Liège, and in 1940 moved to a similar chair at Utrecht in Holland. Prof. Rosenfeld is one of the leading theoretical physicists of to-day and is distinguished not only for his great original contributions to the most difficult and deep parts of modern quantum mechanics and nuclear structure, but also for his wide knowledge and scholarship. He is now completing a book on the quantum theory of nuclear forces which should prove valuable to all theoretical workers on nuclear structure. In his new position in Manchester he will add greatly to the strength of theoretical physics in England. He will be in very close touch with the experimental researches being carried out in the laboratory of Prof. P. M. S. Blackett.