Einstein famously posited, 'Everything should be made as simple as possible, but not simpler.' This modern corollary to Occam's Razor is often honored in the breach, especially the final three words, and especially in the IT industry. Distributed systems, like security and error handling, are inherently difficult, and no amount of layered abstraction will overcome that simple fact. A deep understanding of what makes distributed systems architecture different from monolithic systems architecture is critically important in a networked world of services such as that promised by Service Oriented Architecture, and Puder, Römer and Pilhofer deliver that deep understanding in a straightforward, step-by-step fashion, from the inside out—as simple as possible, but not simpler. Every application developer today is a distributed systems developer, and this book therefore belongs on the bookshelf of every developer, architect and development manager