Before beginning our exposition of Sartre's L'Être et le Néant, it is necessary to forewarn the reader that both the style and the content of Sartre's main work offer a serious problem in any attempt to present lucidly his ideas and intentions or to translate his language into intelligible English. It is impossible to convey to anyone who has not read L'Être et le Néant the involved and often tangled line of Sartre's argument and the horrifying quality of the prose which is intended to convey the author's ideas. In addition to seemingly endless sentences and ambiguous repetitions, the author uses words that do not appear in any dictionary. Sartre invents a new terminology to meet the requirements of the radical ontology he presents. Thus, nouns are used as verbs, and new grammatical constructions are invented to meet the author's needs. What emerges from this strange new language is an ontological structure of Gargantuan length and complexity. We must beg the reader's indulgence in the following pages and hope that he will realize that much of the difficulty of the exposition is necessitated by the nature of the material presented. In many cases it is simply impossible to render the argument in simpler language without danger of doing violence to the meaning Sartre intends to convey to his reader.