Performance is not simply a matter of tuning the code or the computing environment - it starts with designing performance into the application from the outset, and spans all phases of the system life cycle. Drawing on his 25 years of experience, Chris Loosley explains the principles of software performance engineering and applies them to all facets of distributed systems architecture and design. Along the way, he summarizes his conclusions in over 250 useful, easily referenced guidelines. And he covers all the key topics, with chapters on Middleware, Architecture, Design, Tools, Databases, Replication, Warehousing, and Transaction Monitors. Loosley's conclusions about the architecture and design of enterprise systems challenge many current middleware trends. Applying the performance principles, Loosley explains why the key to creating truly scalable distributed systems is to decompose complex business applications into multitransaction workflows, and to use asynchronous data replication, parallel processing, and batching techniques.