This book is intended for students, teachers, researchers, engineers and project managers wishing to understand and implement systems engineering into their work. Based on numerous bibliographical sources, it provides coherent and accessible information, complemented with numerous illustrations. Systems Engineering will enable the reader to not only understand but also master the development cycle of a system, as well as gain an in-depth understanding of the associated terminology. An introduction to systems theory is presented first, clarifying what is meant by a complex system. The book then outlines systems engineering and one of its components: requirements engineering. A detailed presentation of the downhill activities of the development cycle follows the definition of requirements and the design of systems. Finally, the book explores the upstream activities of the development cycle with the virtual and concrete integration of the system.