What is Existentialism? It is perhaps the most misunderstood of modern philosophic positions misunderstood by reason of its broad popularity and general unfamiliarity with its origins, representatives and principles. Existential thinking does not originate with Jean Paul Sartre. It has prior religious, literary, and philosophic origins. In its narrovest formulation it is a metaphysical doctrine, arguing as it does that any definition of man's essence must follow, not precede, an estimation of his existence. In Heidegger, it affords a view of Being in its totality in Kierkegaard an approach to that in wardness indispensable to outhentic religious experience for Dostoevsky, Kant and Ruke the existential situation bears stamp modern man's alienation, uprootedness and absurdity to Sartre it has vast ethical and political implications.