This document discusses software integration and Mule ESB. It defines software integration as assembling existing applications and data sources to meet enterprise needs. Benefits include cost savings, faster adaptation to changes, and better customer service. Integration patterns described include peer-to-peer, client-server, pipeline, and enterprise application network. Service-oriented architecture (SOA) and enterprise service bus (ESB) are also introduced. Mule ESB is presented as a lightweight, open source ESB that allows easy integration of different systems using protocols like JMS, web services, and HTTP. Reasons to use Mule ESB include its open source nature, platform independence, and support for multiple topologies and protocols.