Although most of Kierkegaard's life was covered by the first half of the nineteenth century—he died in 1855—his influence belongs to the twentieth. Not that he was ignored, by his fellow-countrymen at least, in his own day; on the contrary, he was a conspicuous and controversial figure. But beyond Denmark his voluminous writings made no impact until after the First World War. Since then they have been translated into many languages and the man and his work—for the two are inseparable—have been the subject of endless comment and discussion. Kierkegaard is regarded as the originator— as he remains the most forceful exponent—of the type of modern philosophy known as existentialism, and thinkers as diverse as Karl Jaspers, Karl Barth and Jean-Paul Sartre are alike in being his recognizable heirs.

Born at Copenhagen in 1813, the son of a well-to-do wool merchant, Søren Kierkegaard spent practically the whole of his life in his native city, leaving it only for two or three brief periods—in all but a few months—in Berlin, which he first visited in order to hear Schelling lecture on Hegel, an experience which he found disappointing. The great personal influence in his life was that of his dourly religious father, Michael Pedersen Kierkegaard, who had been brought up in poverty amid the desolate heaths of Jutland but wThose success in business permitted him to retire at the age of 40, soon after the death of his first wife. Soren was the last of seven children by a second marriage to a distant relative whose status in the Kierkegaard household was virtually that of a servant.