Direct Energy Conversion is written for students and practicing engineers with an interest in the performance of energy conversion processes that involve direct methods of producing electric power from heat and other primary sources. It provides an in-depth development of key issues from the first principles of the underlying sciences, and examines the means available for converting heat to electricity without the intermediate generation of rotating shaft power. A physical and quantitative understanding of the limitations of a number of commercially interesting methods is developed in order to allow readers assessment of the technologies for specific applications. The list of processes considered is limited by performance measured in terms of cost, conversion efficiency, and power density. Ideal for senior undergraduate and graduate level courses in power production, energy conversion, and power systems, Direct Energy Conversion is also a natural adjunct to the author's previous text, Energy Conversion (OUP, 1994), which focuses on the thermodynamics and mechanics of heat.