This book is the direct result of a NATO Advanced Study Institute on "Heat Pumps" held at Les Arcs, France, June 1975, under the director ship of Profes sor E. Camatini, Politecnico di Milano, Italy. Leading world experts in the field were invited to attend this Institute and to lecture on the heat pump and its potential applications in the broader context of energy conservation. The lectures focussed on today's energy problems, fundamental principles of thermodynamics and their application to the heat pump, potential heat sourc es for heat pumps, alternate heat pump drives, heat transport...