Service Oriented Architecture (SOA) is an architectural style that has recently come to prominence. The Open Group has a long history of providing support for enterprise architects, notably through development and maintenance of The Open Group Architecture Framework (TOGAF™). The Open Group is naturally concerned to understand the relation of SOA to other styles of enterprise architecture, and to support enterprise architects using SOA. It has established its SOA Working Group as a vehicle for its work on SOA. This White Paper sets out the understanding that has been reached by the SOA Working Group of SOA and its relation to enterprise architecture, and in particular to TOGAF, in order to: 1. Communicate that understanding to the rest of The Open Group and to the IT industry at large 2. Provide a basis for the further development of the work program of the SOA Working Group