This paper attempts to articulate the general role of infrastructure for multi-agent systems (MAS), and why infrastructure is a particularly critical issue if we are to increase the visibility and impact of multi-agent systems as a universal technology and solution. Second, it presents my current thinking on the socio-technical content of the needed infrastructure in four different corners of the multi-agent systems world: science, education, application, and use. 1 Why MAS Infrastructure is an Issue MAS have the potential to meet two critical near-term needs accompanying the widespread adoption of high-speed, mission-critical content-rich, distributed information systems. First, they can become a fundamental enabling technology, especially in situations where mutual interdependencies, dynamic environments, uncertainty, and sophisticated control play a role. Second, they can provide robust representational theories and very direct modeling technologies to help us understand large, mult...