The present volume is the third of the series on Cybernetics to be published. It gives the impression of being even better than its predecessors. All volumes containing verbatim discussion must have weaknesses; the wonder is that the plan succeeds as well as it does. If we are willing to accept the defects inherent in such a scheme (and the present volume is unintelligible in several places), we shall be rewarded with a grand-stand view of acute minds grappling with difficult problems in borderland fields. The theme of the discussion is different kinds of Communication—between groups, between animals, and so on. Dr. Kubie's contribution on communication between the sane and the insane is perhaps the most striking part of the book.