Building an Enterprise Architecture is not a trivial task; it is one that requires clear objectives, good planning and a disciplined yet flexible approach. It is important to achieve a critical mass of relevant, "joined up" information from which reliable conclusions may be drawn.

The Best Practice Guide "Enterprise Architecture – Understanding the bigger picture" published in 2003, provides an introduction to the ideas of Enterprise Architecture and describes a straightforward, practical method of defining and building a working enterprise architecture.

This guide now follows on and describes the notions of the "Minimum Essential Model" and "Progressive Development" of the Enterprise Architecture. It describes some scenarios where the enterprise architecture can deliver real value – these include business process re-engineering, business service definition, project portfolio planning and service-oriented application design and specification. The required minimum essential models are defined and step-by-step procedures are suggested.

The guide is illustrated with some real-world case studies from the financial services industry which highlight important learning points. These will contribute to the successful development and use of the Enterprise Architecture.