This book focuses on Service Oriented Architecture (SOA), the basis of sustainable and more agile IT systems that are able to adapt themselves to new trends and manage processes involving a third party. The discussion is based on the public Praxeme method and features a number of examples taken from large SOA projects which were used to rewrite the information systems of an insurance company; as such, decision-makers, creators of IT systems, programmers and computer scientists, as well as those who will use these new developments, will find this a useful resource.