Existentialism is less a doctrine than a set of questions that refuse to leave a thinking person alone. What does it mean to be free? How is one to live in a universe that hands down no purpose of its own? Can a life be genuinely made, chosen and authored, rather than merely inherited and performed? The philosophers and novelists we group under the name existentialism did not agree on the answers, and several of them rejected the label outright, yet they were all bent over the same problem: the concrete, existing individual, thrown into a world without a manual, and obliged to decide what to become.

This guide is a map of that territory. It explains what existentialism means, lays out the core ideas that run through it, introduces its major thinkers and their forerunners, and points to the books through which the tradition is best entered. Its two great branches, Sartre’s philosophy of freedom and Camus’s absurdism, together with the individual works and figures, are treated at length in the pieces linked throughout, so that this page can serve as the doorway to all of them.

What Is Existentialism? The Short Answer

Existentialism is a philosophy holding that human beings have no fixed, predetermined essence, and that each person is therefore radically free, and wholly responsible for creating their own meaning and values through the choices they make. In plainer terms: there is no blueprint for what a human being is supposed to be and no purpose assigned in advance, and so the meaning of a life is not discovered but made, by the one living it, through how it is lived.

It is not a single creed but a family of thinkers, often in fierce disagreement, held together by a shared emphasis on the existing individual over abstract systems, and by the conviction that, in Sartre’s famous formula, existence precedes essence. We exist first, and decide what we are afterward.

The Core Ideas of Existentialism

A handful of ideas recur across the tradition, and grasping them is most of the work of understanding existentialism at all.

• Existence precedes essence. We are not made to a design; we exist first, without instructions, and create our essence through what we do. This is the movement’s founding claim, worked out most fully in Sartre’s Being and Nothingness.
• Radical freedom and responsibility. If nothing determines what we are, then we are free at every moment, and can never escape responsibility for our choices. Sartre called this being “condemned to be free.”
• The absurd. For Camus, the human hunger for meaning meets a silent, indifferent universe, and the collision between them is the absurd, the subject of our guide to absurdism.
• Bad faith and authenticity. We constantly flee our freedom by pretending to be fixed things with settled roles, a self-deception Sartre named bad faith; to live authentically is to own that freedom instead of hiding from it.
• Anxiety. The awareness of freedom brings a particular dread, what Kierkegaard called the dizziness of freedom and Heidegger placed at the center of what it is to exist.
• Alienation. The existential self is often estranged, cut off from a world and from systems that no longer make sense, a note that runs from Dostoevsky straight into the kafkaesque.

The Existentialists and Their Forerunners

Existentialism had no founder and no manifesto; it was built by a line of restless minds across more than a century, several of whom would have refused one another’s company.

• Søren Kierkegaard (1813–1855), the Danish forerunner usually called the father of existentialism, who set the individual, faith, and anxiety at the center of thought.
• Friedrich Nietzsche (1844–1900), who announced that “God is dead” and forced the question of how to create values once the old foundations had crumbled.
• Fyodor Dostoevsky (1821–1881), the greatest forerunner in fiction, whose Notes from Underground gave the movement its first spiteful anti-hero.
• Franz Kafka (1883–1924), poet of alienation and the faceless system, whose The Trial rendered the modern individual’s helplessness once and for all.
• Martin Heidegger (1889–1976), whose formidable ontology of being, authenticity, and being-toward-death shaped nearly everything that followed.
• Jean-Paul Sartre (1905–1980), the movement’s public face, whose novel Nausea and treatise Being and Nothingness gave existentialism its fullest form.
• Albert Camus (1913–1960), who mapped the absurd in The Myth of Sisyphus and the ethics of revolt in The Rebel.
• Simone de Beauvoir (1908–1986), who extended existentialist freedom into ethics and the situation of women, and whose life with Sartre is examined in Sartre and Beauvoir in Brazil.

Essential Existentialist Books: Where to Start

Existentialism is unusual among philosophies in that its greatest statements are often novels, which makes it uncommonly easy to enter. For most readers the best first step is Camus’s The Stranger, short and strange and unforgettable, followed by his The Myth of Sisyphus for the philosophy behind it. From there, Sartre’s Nausea delivers the same vision as physical sensation, and Dostoevsky’s Notes from Underground supplies the nineteenth-century root of it all. Kafka’s The Trial carries the mood to its bureaucratic extreme. For the full map of where to go next, our guide to the existentialist books to read after Camus sets out the whole tradition, philosophy and fiction alike.

Existentialism vs Absurdism vs Nihilism

These three are constantly confused, and the differences matter. Existentialism holds that although life has no built-in meaning, we can and must create our own through our free choices. Absurdism, the view Camus developed, doubts even that consolation: it fixes on the confrontation between our need for meaning and the world’s silence, and asks us to live inside that tension without resolving it. Nihilism, by contrast, concludes from the absence of inherent meaning that nothing matters at all, and stops there. Existentialism and absurdism are both, in their different ways, answers to nihilism rather than versions of it. Camus himself rejected the existentialist label for precisely these reasons, a disagreement that hardened into the famous break recounted in the quarrel that divided existentialism.

How to Explore Existentialism

You need not read it all, and certainly not in order. Choose the path that suits you.

• The fiction path: The Stranger → Nausea → The Trial → Notes from Underground. The ideas met as lived experience.
• The philosophy path: Kierkegaard → Nietzsche → Being and Nothingness. The formal argument from its roots.
• The Camus path: The Myth of Sisyphus → The Rebel, entered through absurdism. The absurd, and what follows from it.

The Freedom to Begin

Return, at the end, to the questions with which we began. Existentialism offers no final answers, and it is worth being clear that this is not the same thing as despair, the charge most often laid against it. Its claim is in fact the opposite of despair: that because no essence or destiny is imposed on us from outside, the meaning of a life is genuinely ours to make, and that this freedom, however vertiginous, is also the ground of every human dignity. Camus asked us to imagine Sisyphus happy; Sartre insisted we are the sole authors of ourselves. The tradition hands the reader not a conclusion but a task, and the first step is only to choose a door and enter.