Few organizations have the benefit of starting from scratch, a concept called green-field development, but instead must integrate their new work with existing legacy applications. In section 5.3.5 Enterprise Application Integration From The Ground Up ( Software Development, April 1999), the first of a three-part series, David S. Linthicum presents an overview of the issues surrounding enterprise application integration (EAI). The purpose of EAI is to build seamless bridges between applications within your organization to integrate your disparate applications in such a way as to make them appear to be one, an effort that obviously spans several projects. As organizations move into the hyper-competitive world of the Internet age, they are discovering that their stand-alone stovepipe applications (those that address one specific business need that do not interact with other applications) are insufficient for their modern-day needs. In this article, Linthicum describes EAI as the unrestricted data sharing among any connected applications or data sources in the enterprise. You need to share this data without making sweeping changes to the applications or data structures. In other words, you must leave it where it lies. This is a tall order, and to his credit, Linthicum states that despite the marketing claims of technology vendors, there is still no solution to the EAI problem. He does however lay the groundwork for how to go about EAI, presenting a layered approach for organizing your efforts.