This chapter provides an analysis of nuclear fusion as a “system good.” The approach focusses on the complex interactions along the production chain, from the production of hydrogen isotopes, fuel fabrication, proliferation and weapon issues, to the “back-end,” including decommissioning and waste management. After the conceptual part, the chapter goes on comparing two different organizational models for building magnetic confinement fusion devices. On the one hand, ITER is a huge international public project trying to prove fusion’s technical feasibility with a large-scale reactor. On the other hand, Commonwealth Fusion Systems is a private company with a shorter timeline and commercially driven approach to aiming to build the SPARC reactor. ITER’s collaborative model ensures long-term stability, but introduces delays and complexity, while SPARC’s agile, investor-driven model prioritizes speed and adaptability. Using the system good analysis framework, this chapter analyzes the technological approach, procurement strategies, production processes and funding models of ITER and SPARC. Lessons from these projects—public collaboration and private innovation—can be used to design future fusion systems and advance technology, organization, and resource mobilization.