Christopher Pethick received his D.Phil. degree in 1965 from the University of Oxford. After postdoctoral positions there and at the University of Illinois at Urbana-Champaign, he joined the faculty at Illinois in 1970. He is currently professor at Nordita, the Nordic Institute for Theoretical Physics in Copenhagen.
Henrik Smith obtained his mag. scient. degree in 1966 from the University of Copenhagen, and spent the next few years as a postdoctoral fellow at Cornell University and as a visiting scientist at the Institute for Theoretical Physics, Helsinki. In 1972 he joined the faculty of the University of Copenhagen where he is now a professor at the Orsted Laboratory.
The two authors; have worked together on the properties of superconductors and superfluid 3He, in addition to those of dilute quantum gases. This book derives from graduate-level lectures given by the authors at the University of Copenhagen.