Existentialism is not a school of thought nor reducible to any set of tenets. The three writers who appear invariably on every list of existentialists Jaspers, Heidegger and Sartre are not in agreement on essentials. Such alleged precursors as Pascal and Kierkegaard differed from all three men by being dedicated Christians; and Pascal was a Catholic of sorts while Kierkegaard was Protestant's Protestant. If as is often done Nietzsche and Dostoevsky are included in the fold we must make room for an impassioned anti-Christian and an even more fanatical Greek-Orthodox Russian imperialist.