I’ve targeted this book at architects, designers, and developers of enterprise-class software systems—this includes websites, web services, and EAI projects, among others. To me, enterprise-class simply means that the software must be available, or the company loses money. These might be commerce systems that generate revenue directly through sales or perhaps critical internal systems that employees use to do their jobs. If anybody has to go home for the day because your software stops working, then this book is for you.