Information-rich environments are the open environments that characterize most of the modern applications of computing technology. The applications include ubiquitous information access, electronic commerce, virtual enterprises, logistics, and sensor integration, to name but a few. These applications differ from conventional database applications not only in the nature and variety of information they involve, but also in including a significant component that is beyond the information system per se: the creation, transformation, use, and ultimate fate of information. The environments are typified only by the large amounts and varieties of information they include, and whose effective and efficient management is key to the above applications. Multiagent systems (MAS) are an important paradigm for building complex information systems, especially cooperative ones. We describe how cooperative information system architectures have evolved a set of common types of computational agents. We also describe two approaches that address complementary aspects of MAS construction.