With men, the matter is different. A large proportion of the human race, it is true, is obliged to work so hard in obtaining necessaries that little energy is left over for other purposes; but those whose livelihood is assured do not, on that account, cease to be active. Xerxes had no lack of food or raiment or wives at the time when he embarked upon the Athenian expedition. Newton was certain of material comfort from the moment when he became a Fellow of Trinity, but it was after this that he wrote the Principia. St Francis and Ignatius Loyola had no need to found Orders to escape from want. These were eminent men, but the same characteristic, in varying degrees, is to be found in all but a small exceptionally sluggish minority. Mrs A, who is quite sure of her husband's success in business, and has no fear of the workhouse, likes to be better dressed than Mrs B. although she could escape the danger of pneumonia at much less expense. Both she and Mr A are pleased if he is knighted or elected to Parliament. In day-dreams there is no limit to imagined triumphs, and if they are regarded as possible, efforts will be made to achieve them.

Imagination is the goad that forces human beings into restless exertion after their primary needs have been satisfied. Most of us have known very few moments when we could have said:

If it were now to die,
'Twere now to be most happy, for I fear
My soul hath her content so absolute
That not another comfort like to this
Succeeds in unknown fate.

And in our rare moments of perfect happiness, it is natural, like Othello, to wish for death, since we know that contentment cannot last. What we need for lasting happiness is impossible for human beings: only God can have complete bliss, for His is 'the kingdom and the power and the glory'. Earthly kingdoms are limited by other kingdoms; earthly power is cut short by death; earthly glory, though we build pyramids or be 'married to immortal verse', fades with the passing of centuries. To those who have but little of power and glory, it may seem that a little more would satisfy them, but in this they are mistaken: these desires are insatiable and infinite, and only in the infinitude of God could they find repose.

While animals are content with existence and reproduction, men desire also to expand, and their desires in this respect are limited only by what imagination suggests as possible. Every man would like to be God, if it were possible; some few find it difficult to admit the impossibility. These are the men framed after the model of Milton's Satan, combining, like him, nobility with impiety. By 'impiety' I mean something not dependent upon theological beliefs: I mean refusal to admit the limitations of individual human power. This Titanic combination of nobility with impiety is most notable in the great conquerors, but some element of it is to be found in all men. It is this that makes social cooperation difficult, for each of us would like to conceive of it after the pattern of the cooperation between God and His worshipers, with ourself in the place of God. Hence competition, the need of compromise and government, the impulse to rebellion, with instability and periodic violence. And hence the need of morality to restrain anarchic self-assertion.

Of the infinite desires of man, the chief are the desires for power and glory. These are not identical, though closely allied: the Prime Minister has more power than glory, the King has more glory than power. As a rule, however, the easiest way to obtain glory is to obtain power; this is especially the case as regards the men who are active in relation to public events. The desire for glory, therefore, prompts, in the main, the same actions as are prompted by the desire for power, and the two motives may, for most practical purposes, be regarded as one.

The orthodox economists, as well as Marx, who in this respect agreed with them, were mistaken in supposing that economic self-interest could be taken as the fundamental motive in the social sciences. The desire for commodities, when separated from power and glory, is finite, and can be fully satisfied by a moderate competence. The really expensive desires are not dictated by a love of material comfort. Such commodities as a legislature rendered subservient by corruption, or a private picture gallery of Old Masters selected by experts, are sought for the sake of power or glory, not as affording comfortable places in which to sit. When a moderate degree of comfort is assured, both individuals and communities will pursue power rather than wealth: they may seek wealth as a means to power, or they may forgo an increase of wealth in order to secure an increase of power, but in the former case as in the latter their fundamental motive is not economic.

This error in orthodox and Marxist economics is not merely theoretical, but is of the greatest practical importance, and has caused some of the principal events of recent times to be misunderstood. It is only by realizing that love of power is the cause of the activities that are important in social affairs that history, whether ancient or modern, can be rightly interpreted.

In the course of this book I shall be concerned to prove that the fundamental concept in social science is Power, in the same sense in which Energy is the fundamental concept in physics. Like energy, power has many forms, such as wealth, armaments, civil authority, influence on opinion. No one of these can be regarded as subordinate to any other, and there is no one form from which the others are derivative. The attempt to treat one form of power, say wealth, in isolation, can only be partially successful, just as the study of one form of energy will be defective at certain points, unless other forms are taken into account. Wealth may result from military power or from influence over opinion, just as either of these may result from wealth. The laws of social dynamics are laws which can only be stated in terms of power, not in terms of this or that form of power. In former times, military power was isolated, with the consequence that victory or defeat appeared to depend upon the accidental qualities of commanders. In our day, it is common to treat economic power as the source from which all other kinds are derived; this, I shall contend, is just as great an error as that of the purely military historians whom it has caused to seem out of date. Again, there are those who regard propaganda as the fundamental form of power. This is by no means a new opinion; it is embodied in such traditional sayings as magna est veritas et prevalebit and 'the blood of the martyrs is the seed of the Church'. It has about the same measure of truth and falsehood as the military view or the economic view. Propaganda, if it can create an almost unanimous opinion, can generate an irresistible power; but those who have military or economic control can, if they choose, use it for the purpose of propaganda. To revert to the analogy of physics: power, like energy, must be regarded as continually passing from any one of its forms into any other, and it should be the business of social science to seek the laws of such transformations. The attempt to isolate any one form of power, more especially, in our day, the economic form, has been, and still is, a source of errors of great practical importance.

There are many ways in which different societies differ in relation to power. They differ, to begin with, in the degree of power possessed by individuals or organizations; it is obvious, for example, that, owing to increase of organization, the State has more power now than in former times. They differ, again, as regards the kind of organization that is most influential: a military despotism, a theocracy, a plutocracy, are very dissimilar types. They differ, thirdly, through diversity in the ways of acquiring power: hereditary kingship produces one kind of eminent man, the qualities required of a great ecclesiastic produce another kind, democracy produces a third kind, and war a fourth.

Where no social institution, such as aristocracy or hereditary monarchy, exists to limit the number of men to whom power is possible, those who most desire power are, broadly speaking, those most likely to acquire it. It follows that, in a social system in which power is open to all, the posts which confer power will, as a rule, be occupied by men who differ from the average in being exceptionally power-loving. Love of power, though one of the strongest of human motives, is very unevenly distributed, and is limited by various other motives, such as love of ease, love of pleasure, and sometimes love of approval. It is disguised, among the more timid, as an impulse of submission to leadership, which increases the scope of the power-impulses of bold men. Those whose love of power is not strong are unlikely to have much influence on the course of events. The men who cause social changes are, as a rule, men who strongly desire to do so. Love of power, therefore, is a characteristic of the men who are causally important. We should, of course, be mistaken if we regarded it as the sole human motive, but this mistake would not lead us so much astray as might be expected in the search for causal laws in social science, since love of power is the chief motive producing the changes which social science has to study.

The laws of social dynamics are - so I shall contend - only capable of being stated in terms of power in its various forms. In order to discover these laws, it is necessary first to classify the forms of power, and then to review various important historical examples of the ways in which organizations and individuals have acquired control over men's lives.

I shall have, throughout, the twofold purpose of suggesting what I believe to be a more adequate analysis of social changes in general than that which has been taught by economists, and of making the present and the probable near future more intelligible than it can be to those whose imaginations are dominated by the eighteenth and nineteenth centuries. Those centuries were in many ways exceptional, and we seem to be now returning, in a number of respects, to forms of life and thought which were prevalent in earlier ages. To understand our own time and its needs, history, both ancient and medieval, is indispensable, for only so can we arrive at a form of possible progress not unduly dominated by the axioms of the nineteenth century.