Sartre, the heir of Heidegger as the modern apostle of phenomenological existentialism, is generally regarded as the witness par excellence of our time. As such, Molnar undertakes a critical study of his thought. It is ""critical"" in the sense that the author works his way through the Sartrean corpus, from its genesis through the various ""phases"" of Marxism, picking here, slashing there, cavilling pretty much everywhere, and concluding that Sarlre is ""perhaps the last loyal keeper of the Marxist enclave in Utopia."" One suspects that the author's commitment is to a system radically opposed to that of his subject, and that it is in terms of his own beliefs that he first defines and later attacks Sartre. Molnar's criticisms, for example, seem largely theological in origin, whereas Sartre's thought, in its transformation of Heidegger's suggestive but incomplete concepts into a subtle and intentionally paradoxical system, is almost wholly philosophical. Within that context, it is readily apparent that the author is unable to deal satisfactorily with the humanistic implications of Sartre's basic contention -""existence precedes essence."" The only readership which can be assumed is one predisposed to agree with Mr. Molnar.