Practical engineering systems are frequently confronted with challenges such as nonlinearity, uncertainty, and stringent performance requirements. Consequently, the adaptive constrained control of nonlinear systems has become a prominent and complex topic within the field of control theory. In recent years, the theory of high-order fully actuated systems has attracted considerable attention due to its effectiveness and convenience in addressing these challenges. This open access book presents cutting-edge research on adaptive constrained control for nonlinear systems, grounded in high-order fully actuated system approaches. It brings together a series of innovative studies covering key areas, including adaptive input-constrained control, adaptive time-constrained control, adaptive state-constrained control. Each topic is supported by detailed control design strategies and validated through demonstrations of their practical effectiveness. These contributions not only advance the theoretical development of nonlinear control but also enrich the broader framework of fully actuated system theory. Readers will gain a comprehensive understanding of nonlinear control design methodologies based on high-order fully actuated system theory, along with practical solutions to common control challenges in engineering applications. A foundational knowledge of nonlinear systems and control is recommended. While primarily intended for students and practitioners in control theory, this book also serves as a valuable reference for professionals in related disciplines such as communication engineering and economics. Additionally, it is well-suited for use in advanced academic courses and research seminars.