This document discusses Mule ESB, including its components and scenarios for use. Mule ESB is a lightweight Java-based enterprise service bus that allows developers to quickly connect and exchange data between applications. It contains three main components - the Package Explorer, Palette, and Canvas. The Palette contains connectors, transformers, and filters that can be dragged onto the Canvas to graphically create integration flows. Several example scenarios are provided, such as picking up an XML file from FTP and placing it in a JMS queue, invoking a web service using a scheduler, and sending email alerts for exceptions.