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Reviewer: John J. Hirschfelder

A detailed definition and explanation of the object process method (OPM), a graphical and textual language for modeling systems, is presented in this book. Although OPM is a derivative of object-oriented (OO) methods, as well as earlier methods, it differs fundamentally from OO methods (such as the unified modeling language (UML)) in that objects and processes are treated as independent fundamental concepts. OO methods, by contrast, de-emphasize processes by burying them in the methods associated with object classes. An OPM model can be presented either graphically, in object-process diagrams (OPDs), or in object-process language (OPL). A system model presented as a set of OPDs can be restated uniquely in OPL. Conversely, a system model presented in OPL can be translated into a set of OPDs, unique up to an obvious equivalence. In the graphical presentation of OMP, objects are represented by rectangles, and processes by ovals. A set of states is associated with each object. In order to execute, a process requires the presence of “agents” (human objects) or “instruments” (non-human objects); a process must affect (namely, create, change the state of, or destroy) at least one object. Symbols are defined to represent these and other “procedural links” between objects and processes. In addition, OPM defines four fundamental structural relations among objects and processes. “Aggregation” relates a whole to its parts, for example: “Dipole consists of North Pole and South Pole” (this is a sentence in OPL). “Exhibition” relates an object or process to attributes of that object or process (the attributes themselves are other objects or processes). “Generalization” relates a general object to its specializations, for example, “Man and Woman are Persons” (another OPL sentence). “Instantiation” relates a class to its instances; this corresponds to object-class membership in OO methods. Symbols are defined for these relations, and a variety of other types of “links.” Note that both classes and objects in an OO model appear as objects in OPM. The book is organized into three parts. Part 1, “Foundations of Object-Process Methodology,” introduces the basic OPM concepts, including processes, objects, OPDs, and OPL. Part 2, “Concepts of OPM Systems Modeling,” provides a comprehensive definition of OPM, including the fundamental structural relations, and complexity management through methods of zooming into and out of processes. Part 3, “Building Systems with OPM,” addresses system modeling, lifecycle and evolution, and systems theory. Finally, chapter 15, “Object-Oriented Modeling,” provides a history of the development of OO modeling techniques, with descriptions of many earlier methods, including UML. The weaknesses of these methods are also discussed. The theme is that all pre-OPM methods require multiple independent graphical methods to completely define the structure and behavior of systems, whereas OPM presents all aspects of a system in a uniform graphic or textual language. This is the most interesting chapter in the book; I recommend reading it immediately after reading chapter 1, and re-reading it at the end. Inside the front and back covers are four pages containing definitions of all of the symbols in OPM. A CD-ROM containing three applications is included. OPCAT-I is a simple, stand-alone object-process computer-aided software engineering (CASE) tool that can be used to draw OPDs. OPCAT-II is a Java application that generates OPL from OPDs; it requires that Microsoft Access be installed. Systemantica is a more powerful tool that supports most but not all of the features of OPM as defined in the book; it requires both Access and Visio. An example of a small but complete OPM model (of an automatic teller machine) is presented in an appendix. A comprehensive bibliography is included. The presentation throughout is clear and precise (appropriate to the precise semantics of OPD and OPL), although often dry. Each concept and notation is illustrated with simple examples. Concepts from graph theory are invoked when appropriate, and standard graph-theoretical terminology is used correctly. Online Computing Reviews Service