This book is one of the classics on developing information systems with a business rules approach. Not only does the book give a good overview of the key concepts in business rules, it also lays out the core tasks and techniques for an actual methodology to develop rules-based systems. Barbara brings great experience in database design and other core application development techniques and she weaves the unique tasks and issues of a business rules approach right in. Anyone used to a "traditional" application development approach will find plenty of reference points so they don't get lost and yet all the keys they need to succeed with a need approach based on business rules.
The references to business rules management systems are a little out of date as you would expect given the book is a few years old but the core advice remains as good today as it was then. Although Barb continues to develop her ideas and write on business rules, this book is an excellent reference for anyone planning business rules projects, conducting them or interested in how to start using them. Highly recommended.