SOAP connects two fields that were previously largely unrelated: application middleware and Web publishing.
Consequently, depending on whether your background is in middleware or Web publishing, you might understand SOAP slightly differently. Yet, it's important to realize that it is neither pure middleware nor is it pure Web publishing; it really is the convergence of the two.
The best approach to understanding the dual nature of SOAP is a historical one. If you review the concepts and trends that led to the development of SOAP, you will be better prepared to study it.
One of the goals of SOAP is to use XML to enable remote procedure calls (RPCs) over HTTP. Originally RPC was developed by the Open Group ( ...