Book excerpt: Complex products, such as airplanes and automobiles, are designed by networks of design teams working on different components, often across organizations. The challenge in managing these networks is to decompose the project into manageable pieces but then coordinate the entire network to produce the best overall design. In this chapter, Manuel Sosa offers insights on this challenge. He examines the design structure matrix (DSM) as a project management tool for planning complex development efforts and discusses the engineering and managerial implications of considering complex products as networks of interconnected subsystems and components. In particular, he considers the impact of modularity on interactions among subcomponents. Finally, he examines organizational communications, overlaying product interfaces with communications interfaces of development teams to understand where communication links may be missing or unnecessary. The discussion offers insights on any complex design and coordination challenge, where networks of individuals or teams work together to contribute to a larger whole.