This paper describes several different approaches for information agents to communicate and cooperate with each other in agent-based systems. The paper describes different communication patterns for inter-agent cooperation. In particular, three patterns of inter-agent communication are described in more detail, brokered communication, subscription/notification communication, and negotiated communication. In each case, the pattern is described and examples of its use are given. The cooperative inter-agent interactions are described in the Unified Modeling Language (UML) notation. Agent-based systems can be designed using these different patterns of interagent communication. Examples are given from electronic commerce, realtime monitoring, and travel reservation systems.