This textbook accommodates the two divergent developmental paths which have become solidly established in the field of fusion energy: the process of sequential tokamak development toward a prototype and the need for a more fundamental and integrative research approach before costly design choices are made.Emphasis is placed on the development of physically coherent and mathematically clear characterizations of the scientific and technological foundations of fusion energy which are specifically suitable for a first course on the subject. Of interest, therefore, are selected aspects of nuclear physics, electromagnetics, plasma physics, reaction dynamics, materials science, and engineering systems, all brought together to form an integrated perspective on nuclear fusion and its practical utilization.The book identifies several distinct themes. The first is concerned with preliminary and introductory topics which relate to the basic and relevant physical processes associated with nuclear fusion. Then, the authors undertake an analysis of magnetically confined, inertially confined, and low-temperature fusion energy concepts. Subsequently, they introduce the important blanket domains surrounding the fusion core and discuss synergetic fusion-fission systems. Finally, they consider selected conceptual and technological subjects germane to the continuing development of fusion energy systems.