Bush was beginning to overcome the technical obstacles that stood in the way of the construction of the differential analyzer, the preWorld War It forerunner of modern high-speed computing machinery. Wiener's close contact with this program and his joint work with Y. W. Lee on the design of electric circuits, led him to consider, most often in the abstract, the potentialities of the computers of the future and to search for criteria and concepts that would make it possible to separate message from adventitious noise. This was also the period during which Arturo Rosenblueth and Norbert Wiener examined closelyÑin a series of monthly discussion meetings how the scientific method was being applied in a variety of fields.

During World War II Norbert Wiener worked on the design of fire control apparatus for anti-aircraft guns. In some sense this problem seemed to be tailor-made for him since it permitted him to pull together many of his previous interests: Wiener saw with great clarity the close relation between the statistical study of time series and the formulation of the basic task of communication engineering, namely the transmission of messages. For a message to be transmitted there must be a repertory or ensemble of possible messages and a way of assessing the probability of these messages. These topics when joined to the problems of filtering and prediction from existing time series comprise the substance of a book that Wiener wrote under the title of Extrapolation, interpolation and smoothing of stationary time series (with engineering applications). (During the war it was known by the more picturesque title of the "Yellow PerilsÑthe cover contributed the adjective.)

The study of fire-control problems led Wiener, for the first time, to deal directly with man in his coupling to a machine. Human sensory and motor abilities were involved in tracking behavior. The way man corrects for errors led to a general consideration of feedback mechanisms in stabilizing performance and of the particular pathology known as "hunting" in the presence of overapplication of feedback.

The type of analysis Wiener and his co-workers used was not too different in inspiration from the homeostatic, error-correcting mechanisms Cannon had dealt with, both conceptually and experimentally. Wiener and his engineering associate, Bigelow, therefore quite naturally consulted with Arturo Rosenblueth on "intention tremorsX as the human pathological symptom that was most closely akin to the pathology encountered in servomechanisms. From this collaboration resulted the famous manifesto, "Behavior, Purpose and Teleology"

Wiener emerged from this wartime work with a conviction that communications engineering, the behavior of servomechanisms, of computing machines and of the nervous system, could all be regarded from a unified overall viewpoint. Drawn by his enthusiasm, people from these disciplines and fields gathered around Wiener in Princeton in a meeting that foreshadowed the famous Macy Foundation series of conferences on Cybernetics.

These conferences, which were the prototype of the many multidisciplinary symposia that followed in the next two decades, subjected the fields that came to be known as sciences of communication to a searching examination. To Wiener and many of his colleagues, communication was clearly the cement of the nervous system, of society, of any complexly organized structure. There was less than unanimity among them and the scientific community at large as to whether cybernetics was a unifying science, a common basis for thought, a convenient common language for functionally related problems, a set of analogies or a program. Many sensational, sciencefictionish tales have been written and told under the cybernetic label (not by Wiener who when writing science fiction stories labeled them accordingly) but often by people of whom he was not as critical as he was of his closer colleagues.

The question has often been asked what specifically has Wiener (or cybernetics) contributed to fields other than mathematics. In the area of engineering there can be no doubt that his lifelong association with colleagues and problems has left a profound mark upon the way much of engineering is practiced, conceptualized and taught. When it comes to the biological sciences, it is much harder to identify discrete contributions that he has made or problems that he has "solved." Since neither of us was trained in this area of science, we feel compelled to be cautious. But it seems that the work Wiener did (mainly with Rosenblueth) and especially the work he stimulated on such topics as biological regulation, characterization of the electroencephalogram as a time series, prosthetic devices, and much else has been of real substance and significance.

We had the good fortune to belong to the post-World War II Wiener Supper Seminar, we were his colleagues on the M.I.T. faculty, and saw at first hand his influence pervade the Institute and, in particular, the Research Laboratory of Electronics. We can offer personal testimony to the quasigenerality of his own remarks on his cooperation with the outstanding British mathematician Paley [92]; he wrote, "My role was primarily that of suggesting problems and the broad lines on which they might be attacked, and it was generally left to Paley to draw the strings tight.n We, too, felt enriched by the problems he suggested and by the excitement he generated by his views of what needed to be done.

In areas in which Wiener's intuition was less educated than in engineering, he was often impatient with experimental details; for example, he seemed sometimes unwilling to learn that the brain did not behave the way he expected it to. Yet even those who have been most critical of his interpretation of data and his speculations can not fail to pay homage to the seminal influence he has exercised by acquainting many a scientist with a different kind of potentially relevant concepts and mathematical and engineering techniques. He had relatively little contact with the spectacular progress in molecular biology which took place after Cybernetics [1381 had been written. This is a pity; for these challenging problems of the flow of intra- and inter-cellular information might have benefitted from an attack by his fertile intellect. He might have found here a still deeper understanding of the logical processes that are at work in living systems, whose nature so intrigued him.

Wiener solved neither all the problems of the brain nor those of the communication sciences; but he articulated them and gave many scientists a new way of looking at some of the most puzzling questions.

Our country was indeed fortunate to have had the complementary influences of Wiener, Von Neumann and Shannon at work in the immediate postwar period when our educational institutions went through a great expansion in research and graduate study. It wasunder the auspices of this Zeigeist that young people from such different fields as neurophysiology, experimental psychology, linguistics and communication engineering started to learn and integrate into their professional lives the kinds of mathematical skills that their elders had just barely become familiar with under the name of cybernetics.