Blackham offers a clear, concise, and well-written introduction to the often difficult works of Kierkegaard, Nietzsche, Heidegger, Sartre, Jaspers, and Marcel. He summarizes objectively, with no interpretation to suit his beliefs, but gives criticism which shows the weaknesses of their individual thought.
At the end, he gives an overview of the existential philosophy. The tension between consciousness and Being, a mystery which cannot be defined, yet is the reality of humankind, is the preoccupation of these philosophers, as philosophy's attempt to rationalize the universe, eradicating being, has tottered and now crumbled.
In brief, this is a helpful guide to works that can be cryptic or impenetrable. Recommended to any who want the tenets of existentialism elucidated.