This full-color textbook provides an up to date introduction to nuclear physics, reactor design, thermal-hydraulic systems, fuel cycles, safety, and computational methods for students taking a first course in Nuclear Engineering. Following a structured learning approach, the text offers consistent topic development, supported by color images, key equations, worked examples, historical and biographical features, web links for research, short answer questions, and numerous chapter problems. Nuclear reactor designs, including the most recent examples, are analyzed and compared, and the role of internet tools in analysis and design is explored. Extensive tables are included for reference.