Part 1: Systems of systems: concepts and practical illustrations is a multidisciplinary work on the concept of the systems-of-systems that is discussed extensively in current literature. After a critical comparison of the different definitions and a range of various practical illustrations, it provides key answers as to what a system of systems is and how its complexity can be mastered. Part 2: Systems-of-systems engineering: methods and tools focuses on both engineering and modeling, and standardization issues which are critical in order to deal with the key steps of systems-of-systems engineering: elicitation of stakeholders’ needs, architecture optimization, integration of constituent systems, qualification and utilization.