Review of Probabilistic Reasoning in Expert Systems From: Mathematical Reviews, September, 1991, Vol. 91i The book under review is a self-contained introduction to probabilistic reasoning in expert systems, written from the perspective of a mathematician, with the emphasis on the development of theorems and applications. A great deal of attention is given to graph-theoretic considerations concerning triangulated graphs (and methods of triangularization of graphs) and directed acyclic graphs; all necessary facts are carefully proven and applicable algorithms presented. Using this background, together with elements of probability theory, as the core of the book, the author introduces causal networks linking concepts of conditional stochastic independence with graph structures. In this way, indispensable tools for knowledge representation and processing are established. In particular, probability propagation in singly connected causal networks is discussed in detail, as well as probability propagation in trees of cliques. The chapters on rule-based systems and applications in decision theory can be considered as complementary. The book is well suited to serve as a reference book for a practitioner or as the basis for a graduate-level course in the topic. - Tom  Havr nek (CS-CSAV-C)