Cybernetics was defined by Wiener as “the science of control and communication, in the animal and the machine” — in a word, as the art of steermanship, and it is to this aspect that the book will be addressed. Co-ordination, regulation and control will be its themes, for these are of the greatest biological and practical interest.
We must, therefore, make a study of mechanism; but some introduction is advisable, for cybernetics treats the subject from a new, and therefore unusual, angle... The new point of view should be clearly understood, for any unconscious vacillation between the old and the new is apt to lead to confusion.

While studying antiaircraft fire control, Wiener may have conceived the idea of considering the operator as part of the steering mechanism and of applying to him such notions as feedback and stability, which had been devised for mechanical systems and electrical circuits. No doubt this kind of analogy had been operative in Wiener’s mathematical work from the beginning and sometimes had even been productive. As time passed, such flashes of insight were more consciously put to use in a sort of biological research for which Wiener consulted all kinds of people, except mathematicians, whether or not they had anything to do with it. Cybernetics, or Control and Communication in the Animal and the Machine (1948) is a rather eloquent report of these abortive attempts, in the sense that it shows there is not much to be reported. The value and influence of Cybernetics, and other publications of this kind, should not, however, be belittled. It has contributed to popularizing a way of thinking in communication theory terms, such as feedback, information, control, input, output, stability, homeostasis, prediction, and filtering . On the other hand, it also has contributed to spreading mistaken ideas of what mathematics really means

Cybernetics is a young discipline which, like applied mathematics, cuts across the entrenched departments of natural science; the sky, the earth, the animals and the plants. Its interdisciplinary character emerges when it considers economy not as an economist, biology not as a biologist, engines not as an engineer. In each case its theme remains the same, namely, how systems regulate themselves, reproduce themselves, evolve and learn. Its high spot is the question of how they organize themselves. A cybernetic laboratory has a varied worksheet - concept formation in organized groups, teaching machines, brain models, and chemical computers for use in a cybernetic factory. As pure scientists we are concerned with brain-like artifacts, with evolution, growth and development; with the process of thinking and getting to know about the world. Wearing the hat of applied science, we aim to create what Boulanger,' in his presidential address to the International Association of Cybernetics, called the instruments of a new industrial revolution - control mechanisms that lay their own plans.

The essence of cybernetic organizations is that they are self-controlling, self-maintaining, self-realizing. Indeed, cybernetics has been characterized as the “science of effective organization,” in just these terms. But the word “cybernetics” conjures, in the minds of an apparently great number of people, visions of computerized information networks, closed loop systems, and robotized man-surrogates, such as “artorgas” and “cyborgs.”

Cybernetics treats not things but ways of behaving. It does not ask “what is this thing?” but “what does it do?”... It is thus essentially functional and behaviouristic. Cybernetics deals with all forms of behavior in so far as they are regular, or determinate, or reproducible. The materiality is irrelevant... The truths of cybernetics are not conditional on their being derived from some other branch of science. Cybernetics has its own foundations.

Cybernetics is concerned primarily with the construction of theories and models in science, without making a hard and fast distinction between the physical and the biological sciences. The theories and models occur both in symbols and in hardware, and by 'hardware* we shall mean a machine or computer built in terms of physical or chemical, or indeed any handleable parts. Most usually we shall think of hardware as meaning electronic parts such as valves and relays. Cybernetics insists, also, on a further and rather special condition that distinguishes it from ordinary scientific theorizing: it demands a certain standard of effectiveness... The concept of an effective procedure springs primarily from mathematics, where it is called an algorithm... The principal aims of cybernetics may be listed under three headings: (1) To construct an effective theory... [of] the principal functions of the human organism... (2) To produce the models and theory in a manner that realizes the functions of human behaviour by the same logical means as in human beings. This implies the simulation of human operations by machines... (3) To produce models which are constructed from the same colloidal chemical fabrics as are used in human beings.

For me, as I later came to say, cybernetics is the art of creating equilibrium in a world of possibilities and constraints. This is not just a romantic description, it portrays the new way of thinking quite accurately. Cybernetics differs from the traditional scientific procedure, because it does not try to explain phenomena by searching for their causes, but rather by specifying the constraints that determine the direction of their development.

According to the science of cybernetics, which deals with the topic of control in every kind of system (mechanical, electronic, biological, human, economic, and so on), there is a natural law that governs the capacity of a control system to work. It says that the control must be capable of generating as much "variety" as the situation to be controlled.

Cybernetics offers a scientific approach to the cussedness of organisms, suggests how their behaviours can be catalysed and the mystique and rule of thumb banished.

The celebrated physicist and mathematician A.M. Ampere coined the word cybernetique to mean the science of civil government (Part II of "Essai sur la philosophic des sciences", 1845, Paris). Ampere's grandiose scheme of political sciences has not, and perhaps never will, come to fruition. In the meantime, conflict between governments with the use of force greatly accelerated the development of another branch of science, the science of control and guidance of mechanical and electrical systems. It is thus perhaps ironical that Ampere's word should be borrowed by N. Wiener to name this new science, so important to modern warfare. The "cybernetics" of Wiener ("Cybernetics, or Control and Communication in the animal and the Machine," John Wiley & Sons, Inc., New York, 1948) is the science of organization of mechanical and electrical components for stability and purposeful actions. A distinguishing feature of this new science is the total absence of considerations of energy, heat, and efficiency, which are so important in other natural sciences. In fact, the primary concern of cybernetics is on the qualitative aspects of the interrelations among the various components of a system and the synthetic behavior of the complete mechanism.

Cybernetics is the study of systems and processes that interact with themselves and produce themselves from themselves.

The word 'cybernetics' is still new to many people, even though it has now been an accepted word of our language for some ten or fifteen years. Speaking generally, cybernetics is the scientific study of control and communication. It is an attempt to give an integrated account of both physical and biological systems in terms of their capacity to communicate between different points of the system, and in terms of their control. There has been considerable research into general methods of communication in recent years, and this has been primarily the work of communication engineers, who are trying to discover in general terms what they themselves are doing.

My analysis of living systems uses concepts of thermodynamics, information theory, cybernetics, and systems engineering, as well as the classical concepts appropriate to each level. The purpose is to produce a description of living structure and process in terms of input and output, flows through systems, steady states, and feedbacks, which will clarify and unify the facts of life.

Cybernetics as a specific field grew out of a series of interdisciplinary meetings held from 1944 to 1953 that brought together a number of noted post-war intellectuals, including Wiener, John von Neumann, Warren McCulloch, Claude Shannon, Heinz von Foerster, W. Ross Ashby, Gregory Bateson and Margaret Mead. Hosted by the Josiah Macy Jr. Foundation, these became known as the Macy Conferences on Cybernetics. From its original focus on machines and animals, cybernetics quickly broadened to encompass minds (e.g. in the work of Bateson and Ashby) and social systems (e.g. Stafford Beer's management cybernetics), thus recovering Plato's original focus on the control relations in society. Through the 1950s, cybernetic thinkers came to cohere with the school of General Systems Theory (GST), founded at about the same time by Ludwig von Bertalanffy, as an attempt to build a unified science by uncovering the common principles that govern open, evolving systems. GST studies systems at all levels of generality, whereas Cybernetics focuses more specifically on goal-directed, functional systems which have some form of control relation.