This document discusses software integration challenges and how an Enterprise Service Bus (ESB) and Mule ESB can address them. It describes integration patterns like peer-to-peer and hub-and-spoke. An ESB is middleware that connects applications and allows them to communicate through features like routing, messaging and transformation. Mule ESB is an open source ESB that enables quick and easy integration of existing systems regardless of technology. It supports protocols, services, APIs and topologies like routers, filters and transformers. The document provides an example of how Mule ESB can be used to create a loan broker application.