Existentialism was a disparate philosophical movement that emerged in the nineteenth century through the writings of Soren Kierkegaard, Friedrich Nietzsche, and Fyodor Dostoyevsky. Largely focusing on the individual and the subjectivity of human thought, existentialism was a critical reaction to philosophers such as Immanuel Kant and Georg Wilhelm Friedrich Hegel. Existentialism would further develop in France during the first half of the twentieth century thanks to figures like Jean-Paul Sartre, Simone de Beauvoir, and Albert Camus.

Edward Saïd is a writer most well-known for his book Orientalism, which was published in 1978.

In Cold Blood was considered the first "non-fiction novel" shortly after the book's publication. Its author, Truman Capote, was already an acclaimed author, and sought out the story of two murderers, Richard Hickock and Perry Smith. Capote interviewed and talked with the murderers for over a year to craft his book, which became a bestseller as soon as it was published.

The Myth of Sisyphus, written by Albert Camus during the Nazi Occupation of France in World War II, uses the ancient story of Sisyphus to explain life. Just as Sisyphus was doomed to continually push a rock up a hill, Camus argued people had a life with little meaning. Nonetheless, he argued that humans should strive to rebel against the absurdity of such a life.

Bertrand Russell was one of the foremost and earliest articulators of an atheist position. By affirming what he did believe, Russell made his mark in religious discussions with his Why I am Not a Christian. The work would prove influential for many more anti-Christian and atheist works in subsequent decades.

After the heterodox Christian Søren Kierkegaard in the nineteenth century, the philosophical movement known as existentialism was largely picked up by atheists. However, in the post-World War II period, the Christian theologian Paul Tillich embraced many of existentialism's chief tenets, including alienation, an inability to know things concretely, and the desire for an authentic life. This made Tillich simultaneously controversial and widely celebrated.

Rainer Maria Rilke was a poet universally described as "mystical," and always attracted a large following from the time he first published in the 1890s. Franz Xaver Kappus, a nineteen-year-old cadet at the Theresian Military Academy, received ten letters on poetry from Rilke from 1902 to 1908. In 1928, three years after Rilke died of leukemia, Kappus collected and published the letters as Letters to a Young Poet.

Martin Heidegger believed that philosophers since Plato had misunderstood the concept of "being." Heidegger objected to philosophy consistently studying "beings," but rarely ever "being itself." Heidegger's 1927 book Being and Time attempted to correct this problem, but was rushed to publication and only covered a fraction of what he wanted to cover in his work.

Educated as psychiatrist, Frantz Fanon was born in Martinique and lived for a long time in Algeria, where he fought in the Algerian revolution against France. As a black man fighting against European powers, Fanon developed many theories about the psychological effect of colonialism. His final work, The Wretched of the Earth, made as he was dying of leukemia in 1961, argued that a colonial people had the right to fight their rulers and demand their freedom, and became highly influential for a variety of left wing revolutionaries in the late twentieth century.

Ludwig Wittgenstein's considerable fame as a philosopher comes on the strength of just two books. Tractatus Logico-Philosophicus was a slim book published in 1921, while Wittgenstein's Philosophical Investigations were compiled after his death from his notebooks and published in 1953. The Philosophical Investigations were largely a refutation and rebuttal of Wittgenstein's earlier work.