Of all the major Western philosophers, Hegel has led the reputation of being the most impenetrable. Hegel was a formidable critic of his predecessor Immanuel Kant and a formative influence on Karl Marx. Through his influence on Marx, Hegel's thought has changed the course of nineteenth- and twentieth-century history. 
Hegel lived and worked in what we now know as Germany, although in his time the many independent states of the region had not been united into one nation. He became of age at the time of the French Revolution, sharing what he later called "the jubilation of his epoch". His career included periods as a private tutor, and nine years as the headmaster of a secondary school, before his growing reputation gained him a university chair. He ended his days as Professor of Philosophy at the University of Berlin, which under the reformed Prussian monarchy was lecturing the intellectual Centre of the German states. 
Hegel wrote several long and dense books, of which the most important are The Phenomenology of Mind, The Science of Logic, and The Philosophy of Right. His Encyclopedia of the Philosophical Sciences is a summary version of his philosophical system. A number of other works were delivered as lectures, and in some cases published after his death from his lecture notes. These include his Lectures on the Philosophy of History, Lectures on Aesthetics, Lectures on the Philosophy of Religion, and Lectures on the History of Philosophy. 
Hegel is a difficult thinker because all his work reflects a systematic view of the world, and he makes few concessions to those not familiar with his way of thinking. In addition his style is anything but user-friendly, at first glance most readers will find his sentences simply incomprehensible. This has led some to denounce him as a charlatan, hiding an emptiness of thought behind a deliberate obscurity of expression in order to give an air of profundity. Yet the meaning of Hegel's writing does, eventually, become apparent after careful study. Though his philosophical system as a whole finds few adherents today, his writings yield original insights and arguments that illuminate many philosophical, social, and political issues. 
The easiest point of entry to Hegel's thought is his Lectures on the Philosophy of His Story. One of Hegel's greatest contributions to our intellectual heritage is -as Marx appreciated- his grasp of the historically conditioned nature of our thinking. One might ask why a philosopher should write a work, that is in one sense a brief outline of the history of the world, from ancient times to his own day. The answer is that for Hegel the facts of history are raw material to which the philosopher must give some sense. For Hegel thought that history displays a rational process of development, and, by studying it, we can understand our own nature and place in the world. This idea of history having meaning can be interpreted as a rewarding of the religious idea that the world was created by a being with some purpose in mind; but it may also be understood in a more limited way, as a claim that history has a direction that we can discern, and is heading to a goal that we can welcome. 
Hegel presents his view of the direction of his story in a famous sentence from the introduction to The Philosophy of History: The history of the world is none other than the progress of the consciousness of freedom. The remainder of the work is a long illustration of this thought. Hegel begins with the ancient empires of China, India, and Persia. Here, he says, only one individual -the ruler- is free. The subjects of these oriental despots, Hegel thought, lacked not merely political freedom, but even the very awareness that they are capable of forming their own judgements about right or wrong. It was only in ancient Greece that the principle of free individual thinking developed, and even then Hegel saw the Greeks as so closely identified with their city-state, and so much ruled by its habits and customs, that they did not see themselves as independent individuals in the modern sense. Though the spark of individuality was lit by the critical thinking of Socrates, individuality did not triumph until the Protestant Reformation recognized that each individual can find his or her own salvation, and gave the right of individual conscience its proper place. 
For Hegel the course of history since the Reformation has been governed by the need to transform the world so as to reflect the newly recognized principle of individual freedom. The era of the Enlightenment, culminating in the French Revolution, was an attempt to abolish every institution that depended on mere custom, and instead ensure that the light of reason, which every individual can freely assent, guides every aspect of our political and social lives. To Hegel this attempt was on a glorious mental dawn: the understanding that thought ought to govern reality, instead of the other way around. Yet the French revolutionaries misunderstood reason, taking it in too abstract a way, without considering the nature of existing communities and the way in which these communities have formed their inhabitants. Thus, the abstract universalism of the Enlightenment led to the excesses of the Guillotine. Yet now that we understand what is needed Hegel concluded, a fully rational organization of the world -and a truly free community- is ready to unfold. 
Hegel's conception of freedom is central to his thought but it often misleads modern readers brought up on a conception of freedom made popular through the writings of such classical liberal thinkers as John Stuart Mill. According to the standard liberal conception: I am free when I am left alone, not interfered with, and able to choose as I please. *(Freedom and determinism; liberty; political freedom). This is, for example, the sense of freedom used by economists who picture consumers as free when there are no restrictions on the goods and services they can choose to buy in a free market. Hegel thought this an utterly superficial notion of freedom, because it does not probe beneath the surface and ask why individuals make the choices they do. Hegel saw these choices as often determined by external forces, which effectively control us. He even anticipates, by more than a century, the modern critique of the consumer society, as creating needs in order to satisfy them: he points out that the need for greater "comfort" does not arise within us, but is suggested to you by those who hope to make a profit from its creation. 
Behind such insights lies Hegel's grasp of history as a process that shapes our choices and our very nature. So to be left alone to make our own choices without interference by others is not to be free it is merely to be subjected to the historical forces of our own times. Real freedom begins with the realization that instead of allowing these forces to control us, we can take control of them. But how can this happen? As long as we see ourselves as independent beings with conflicting wills, we will always regard the existence of other human beings as something alien to ourselves, placing limits on our own freedom. In the classical liberal tradition, that is simply the way the world is, and there is nothing that can be done about it, For Hegel, however, the problem is overcome when we recognize that all human beings share a common ability to reason. Hence if a community can be built on a rational basis, every human being can accept it, not as something alien, but as an expression of his or her own rational will. Our duty and our self-interest will then coincide, for our duty will be rationally based, and our true interest is to realize our nature as a rational being. 
In his belief that we are free only when we act in accordance with our reason, Hegel is in agreement with Kant: and so too when he sees our duty as based on our reason; but Hegel criticized Kant's notion of morality, based as it is on a categorical imperative derived from pure reason, as too abstract, a bare formal framework lacking all content. Moreover, on Kant's view human beings are destined for perpetual conflict between duty and interest. They will always be subject to desires that they must suppress if they are to act as the categorical imperative commands. A purely rational morality like Kant's, Hegel thought, needs to be combined in some way with the ethical customs that are part of our nature as beings of a particular time and place. Thus Hegel sought a synthesis between our concrete ethical nature, formed in a specific community, and the rational aspect of our being. When this synthesis was achieved, we would have a community in which each of us would find our own fulfillment, while contributing to the well being of the whole. We would be free both in the subjective sense in that we could do as we wished to do, and in the objective sense, in that we would rationally determine the course of our history, instead of being determined by it This would then be a truly rational state, reconciling individual freedom with the values of community. 
In The Philosophy of Right, Hegel describes this rational community- in a manner that parallels - though is not identical with- the Prussian monarchy of his own day. For this he was accused by Schopenhauer of selling himself to his employer. After Hegel's death, the Young Hegelians, a group of young radicals that for a time included Marx among its members, thought that in The Philosophy of Right Hegel had betrayed the essence of his own philosophy. They determined to develop his ideas in a way that was truer to the core of his thought than Hegel himself had been. From this group arose the criticism of religion developed by Bruno Bauer and Ludwig Feuerbach, Max Stiner's individual anarchism, developed in his The Ego and its Own, and such early writings of Man as The Economic and Philosophical Manuscripts of 1844 and The German Ideology. 
More recently Karl Popper has seen Hegel as a precursor of the modern totalitarian state. Popper argues that by exalting the rational state and using the concept of freedom in a way that denies that irrational choices are truly free, Hegel made it possible for later authoritarian rulers to justify their tyranny by saying that they must force their citizens to be free. It may be true that Hegel's philosophy is open to this misreading, but it is a misreading. The real Hegel supported constitutional monarchy, the rule of law, trial by jury, and (by the standards of his day) considerable freedom of expression. He would never have regarded the kind of state set up by Hitler or Stalin as a rational state with free citizens. 
Yet Popper has touched on a real problem in Hegel's philosophy. Hegel was driven by an extra ordinary optimism about the prospects of overcoming conflict between human beings, and hence of bringing about a rational and harmonious community. The roots of this optimistic view lie in his metaphysics, and especially in his concept of Geist. This German word can be rendered in English, according to the context, either as "spirit" or as "mind". In the former sense if one can have religious connotations; in the second it is the normal word used to describe the mental or intellectual side of our being, as distinct from the physical. Because the German term covers both these meanings, Hegel is able to use it in a way that suggests an overarching collective Mind that is an active force throughout history, and of which all individual minds -that is all human beings, considered in their mental aspect- are a part. Thus Hegel sees the study of history as a way of getting to know the nature of Geist, and sees the rational state as Geist objectified. Since there is no ideal English translation, I shall henceforth use the capitalized term Mind to express Hegel's concept of Geist. 
Hegel's greatest work is his The Phenomenology of Mind (sometimes referred to in English as The Phenomenology of Spirit) described by Marx as "the true birthplace and secret of Hegel's philosophy". In it Hegel seeks to show that all human intellectual development up to now is the logically necessary working out of Mind's coming to know itself. The logic of this process is, however, not the traditional logic of the syllogism, but rather Hegel's own dialectical logic. In dialectical logic, we start from a given position -as an example, we might take to customary ethics of ancient Greece. Then we find that this position contains within itself the seeds of its own destruction, in the form of an internal contradiction. The questioning of a Socrates leads eventually to the downfall of customary ethics, for example, and its replacement during the Reformation by a morality based on individual conscience alone. Yet this too is one-sided and unstable, and so we must move to a third position, the rational community. This third position combines the positive aspects of its two predecessors. 
This dialectic is sometimes referred to as a movement from thesis to antithesis to synthesis. In the example given, the customary morality of ancient Greece is the thesis, the Reformation morality of individual conscience its antithesis, and the rational community is the synthesis of the two. This last is, in Hegel's philosophy of history, the final synthesis, but in other instances, the synthesis of one stage of the dialectic can serve as the thesis for a new dialectical movement. In The Science of Logic, Hegel applies the same method to the abstract categories with which we think. Here Hegel starts with the bare notion of existence, or being, and argues that since this bare notion of being has no content at all, it cannot be anything. Thus it must be nothing, the antithesis of being. Being and nothing, however, are opposites, constantly moving in and apart from each other, they require to be brought together under the synthesis becoming. Then the dialectic moves on, through many more obscure stages, until in the end Hegel claims to be able to demonstrate the necessity of absolute idealism: that is that the only thing that is ultimately real is the absolute idea, which is Mind, knowing itself as all reality. 
Absolute idealism seems a strange doctrine, but it was by no means unique to Hegel. Kant had already argued that the mind constitutes the known universe because we can only know things within a framework of our own creation, namely the categories of time, space, and substance, yet Kant thought that beyond these categories there must be the "thing-in-itself", forever unknowable. In doing away with the thing-in-itself and saying that all we know is also all that there is, Hegel was following the line of Kantian criticism developed earlier by Johann Fichte. 
Both The Phenomenology of Mind and The Science of Logic, then, have the same process as their subject, the process of Mind coming to know itself ultimate reality. In the Phenomenology this process is presented by an attempt to show the logical necessity inherent in the historical development of human consciousness. In the Logic it is shown as a pure dialectical necessity, as (Hegel tells us) showing God as he is in his eternal essence, before the creation of nature and of a finite mind. The Logic is, therefore, by far the more abstract and difficult works. The Phenomenology is by comparison (but only by comparison), a gripping account of how the finite minds of human beings progress to a point at which they can see that the world beyond them is not alien or hostile to them, but a part of themselves. This is so, because Mind alone is all that is real, and each finite mind is a part of Mind. 
One curious aspect of the enterprise of the Phenomenology is that it seeks to understand a process that is completed by the fact that it is understood. The goal of all history is that mind should come to understand itself as the only ultimate reality. When is that understanding first achieved? By Hegel himself in the Phenomenology. If Hegel is to be believed, the closing pages of his masterpiece are no mere description of the culmination of everything that has happened since finite minds were first created: they are that culmination. 
In the light of Hegel's belief that all finite minds share in a greater underlying reality, we can appreciate why he should have believed in the possibility of a form of society that transcended all conflicts between the individual and the collective, and was truly free while at the Same time in no sense anarchic. We can also see why this belief should have made it possible for Hegel's ideas to lead some of his successors, Marx among them, to a similarly misplaced optimism about the possibility of avoiding such conflicts. For while Marx clamed to have rejected the mysticism in which Hegel enveloped his system, Marx never freed himself from the conviction that history is tending toward a final destination in which there will be complete harmony between the interests of the individual and the common interests of the community. That is why he believed that *communism would be a condition in which everyone freely advanced the common interests of all.