One of the foremost resources on existentialism from renowned philosopher, poet, and Nietzsche translator Walter Kaufmann—a must-read for philosophers, both armchair and professional. 

Existentialism from Dostoevsky to Sartre provides basic writings of Dostoevsky, Kierkegaard, Nietzsche, Rilke, Kafka, Ortega, Jaspers, Heidegger, Sartre, and Camus, including some not previously translated, along with an invaluable introductory essay by Walter Kaufmann.