This paper presents "Campus," an environment that allows University of Hagen (Germany) students to connect briefly to the Internet but remain represented by personalized, autonomous agents that can fulfill a variety of information, communication, planning, and cooperation tasks. A brief survey is presented of existing mobile agent system environments, all of which are based on a central architecture requiring one or more servers to be permanently active and reachable. The Agent Application Programming Interface (AAPI) package is introduced; AAPI is an extension of the Java Class Hierarchy that supports the design and implementation of systems of mobile, autonomous agents and is based upon decentralized control structures. Derived from the AAPI package, "Campus" offers a variety of "Campus Intercommunication Agents" that can perform the following functions on behalf of their owners: retrieve information from libraries, search machines, and faculty/registrar blackboards; exchange information with other agents; search for individual agents; cooperate with other agents in setting up individual working groups; enroll their owners into existing working groups; and arrange meetings between owners. A table presents properties of mobile agent systems. Four figures illustrate migration of an AAPI agent, reverse routing, the two-layered network of "Campus," and the agents' docking and route windows. (DLS)