Designing complex systems is about integrating multiple components, but the main challenge is human rather than technical. A technical interface between components A and B requires a human interface between the designer of component A and the designer of component B. When the skills and competencies are multiple, when the teams are split over different departments, if not different companies, they will speak different languages. How can they work together if they don't understand each other? In this book, we will raise awareness of the risks on misunderstandings when teams from different background collaborate on a complex system. We will analyse how it impacts systems design, and propose managerial solutions to handle those risks.