Revision with unchanged content. Service-Oriented Architecture (SOA) has gained a lot of momentum in both the research field and the industry. The result are ever-improving service implementation techniques and market products, however, there is still a lack of support for strategic decision makers in companies. This is a surprising fact, since they are a key role for the successful adoption of an SOA. This book provides architects and managers with the tools that they have been missing so far. First of all, it outlines the context of SOA holistically, so that the reader becomes aware of the various challenges of this new kind of architecture. Thereafter, the Soability model is introduced, which is designed to assess an entire IT environment, consisting of applications, infrastructure, organisation, and exogenous factors, in terms of how well it is able to sup-port an SOA. The book concludes by presenting various ways in which the model can be interpreted and visualised, so that results can be communi-cated, decisions can be made, and improving steps towards an SOA can be taken. The target audience of this book are IT architects and any other role that is responsible for planning or managing a real-world SOA.