The theory of concurrency is a fruitful area of research, which has resulted in a wealth of formalisms for the description and study of concurrent processes. The unique feature of this book is that it unifies different views of concurrency rather than adding another view. The author does so in a clear and convincing fashion.

The three views the author considers are Petri nets, process terms, and logical formulas. Process terms refer to an algebraic description of processes. For example, the equation X = a . b . x describes a process that is repeatedly engaged in action a followed by action b. Logical formulas are trace-based; they are aimed at specifying the communication behaviors of the processes.

The book starts with an introduction, in which the nature of the three views and their relationships are explained by means of a simple example. Of these three views, Petri nets, which describe the operational machine behavior of a process, are the most detailed descriptions. They are the subject of chapter 2. Chapter 3 gives a semantics for Petri nets, a notation for process terms, and a mapping from process terms to Petri nets. This mapping gives an interleaving semantics for process terms.

Process terms describe processes as algebraic expressions. Logical formulas, discussed in chapter 4, describe only external behavior, that is, how processes interact with their environments. Logical formulas are the most abstract description. They are given a semantics that is based on the readiness model, except that it captures liveness as well as safety. The processes are required to be deterministic.

Chapter 5, which addresses the design of concurrent processes, unifies the material. It shows how a design starts with a logical formula as its specification. Subsequently, this specification is systematically transformed into a process term, under invariance of the semantic meaning. During this transformation, mixed terms, composed of both process terms and specifications, are used. Then the mapping introduced in chapter 3 is applied to arrive at a Petri net. The procedure is illustrated by the design of various counters, a scheduler, and a complex readers-writers access protocol. The final chapter discusses extensions and topics for further research.

The three views of concurrency, and the relations exhibited among them, make this book attractive for graduate courses on the theory of concurrency. Unfortunately, the book lacks exercises. It does have excellent references and well-organized author, subject, and symbol indexes.

The book is aimed at graduate students and researchers. It requires the reader to be fluent in such mathematical concepts as sets, relations, functions, and predicate logic, and to be familiar with the basic concepts of automata and regular languages. Readers who enjoy this mathematical maturity will find the book excellent: it is carefully written, and the material is presented in a well-chosen order and at the right level of detail. The author must be a good teacher.