clearly written and developed with order and p resislon, but the effectance of solutions to the illustrative examples is somewhat minimal. This may be in keeping with tim author's statement: "It would have required an excessive increase in the size of the book to delve deeply into the details of the ramifications of the theory. Therefore the author limited himself to the discussion and illustration, by examples, of the fundamental aspects of the theory. Only the minimum information necessary for the investigator is given; moreover, this information is presented at the level of 'engineering' rigor." Such is in tenor, for example, with tim author's thought that though the book is essentially theoretical in nature, it is written "by an engineer for engineers".
The reviewers are of the opinion however that the book is not suitable for classroom use since it assumes a previous knowledge of basic principles of optimal control theory and of pertinent mathematical tools, such as probability theolT, classical variational calculus, dynamic programming, and the maximum principles; also there are no problems for student-exercise work, etc. Similar to the many Russian books now being translated, it is rather of a quasi-treatise nature; it affords a good summary of basic principles of optimal control theory, but it is primarily suited to self-study by those pm'ticularly interested in advanced aspects of the subject.
Some very important aspects of pertinent research were omitted, in particular the Kolmogorov-Wiener theory and the papers developing it, were not included. Since there is an extensive literatm'e in this field, the reviewers consider as a supplementary account to the Wiener-Kolmogorov theory, and of the much more practice-oriented optimal control timory, as complementary to the book under review, the following pertinent but surprisingly little-known (in the U.S.