With the development and wide application of new information technology, the trend of informationization, intelligence and integration for complex systems is becoming increasingly obvious. Various complex systems promote and restrict each other to form an organic system with a feature of system emergence. The goal of these complex systems is to accomplish complex tasks in very complicated and uncertain environments and get better results than people expect. System effectiveness is always used to measure the design quality and capacity of complex systems. It represents the comprehensive capability of a complex system to perform specific tasks under specific conditions. To guide the optimization design process, improve design quality, reduce the design lifecycle and ultimately enhance the overall capabilities of complex systems, it is necessary to find a scientific method to evaluate and optimize the system effectiveness of the complex system. At present, there are many methods to evaluate system effectiveness, but most of the evaluation objects are mainly single equipment or a subsystem. Complex systems have various typical characteristics of large scale, complex relationships, diverse tasks, and typical uncertainties. It is difficult to achieve comprehensive evaluation and it is not effective to use the existing simple methods directly. Because the existing research on comprehensive evaluation of system effectiveness struggles to meet the emergence requirements of complex systems, it is necessary to research and form a comprehensive evaluation and optimization method of system effectiveness for the complex system. The basic theories and applications of effectiveness evaluation and optimization technology are introduced in this book. The book contains nine chapters, the main contents of which are as follows: Introduction; Construction of Effectiveness Evaluation Index System; Mathematical Modeling and Analysis Technology of Effectiveness Index; Analysis Technology of Classical Effectiveness Evaluation; Mission Oriented Effectiveness Evaluation Technology; Operational Effectiveness Sensitivity Analysis Technology; Analysis Technology of System Effectiveness Contribution; Mission oriented Modeling; and Evaluation and Optimization of Complex Systems. The main content of this book includes: the entire analyzing process of system effectiveness and complex system performance; the construction, selection and modeling of the index system; the evaluation of system effectiveness; and the analysis of sensitivity and contribution, among other topics. Each chapter has a close logical relationship, which can help the readers understand the field more easily. This book has strong practicality. Based on the basic theories of various methods, we provide many concrete cases. Readers can quickly apply them to the practice of effectiveness evaluation following the case studies. The authors’ research and applications provide not only theoretical knowledge, but practical knowledge as well. The latest technological developments are also considered. This book mainly discusses the performance evaluation of typical complex systems, focusing on new theories and methods in this field. We believe this can help the development and application of effectiveness evaluation of complex systems. This book can be used as reference material or as a textbook for high grade students and graduated students in computer simulation and system modeling and simulation, control science and engineering. It also has important reference value for researchers and engineers in professional fields such as ship engineering, aircraft guidance and control, and aircraft design.