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Reviewer: John R. Ray

Fowler focuses on the end result of object-oriented analysis and design—the models themselves—rather than on the tools and techniques presented in most methodology books. The first part of the book (chapters 1 through 11) presents patterns from a number of business domains. Initially, patterns for describing relationships that define responsibilities between parties are examined. Next, observation and measurement are considered. Health care items and a number of patterns from corporate financial analyses follow. The author examines the indexing needed when referring specifically to objects in the work environment. Next, he examines basic patterns for accounting, describing how a network of accounts posting rules can form an active accounting system. Planning is examined in terms of the relationship among plans and how to plan and record the use of resources. Fowler analyzes trading in situations where prices are fluid and discusses how price changes affect profits from the trades. The more specialized area of derivative trading is noted as an example of more common problems. This discussion mentions the problems that lead to the building of inheritance hierarchies. Packages of objects and some of the problems of organizing them in a way that improves their maintainability and flexibility are also reported. In chapters 12 through 15, Fowler discusses problems of analysis and some conceptual models that deal with them. Support patterns address problems that arise in building computer systems around these patterns. Fowler considers the architecture for a client/server information system and how such a system can be layered to improve its maintainability. Next, he discusses how conceptual models can be implemented and suggests ways to turn analysis patterns into software. The final part of the book is more abstract, examining modeling techniques and how advanced modeling constructs can be viewed as patterns. This gives a better basis for extending modeling methods to support particular needs. The author notes that his discussion centers on a series of support patterns, since it is understood that conceptual patterns cannot exist in isolation. The support patterns allow for a conceptual model of software conversion that, in turn, fits into the design or architecture of a large information system. The author discusses the reasoning behind each pattern's design, its rules for use, and implementation types. He also provides a set of useful models and information on reuse to improve such work. The book is detailed and thorough, and will be useful in helping to solve modeling problems across various domains.