Existentialist Ontology and Human Consciousness The majority of the distinguished scholarly articles in this volume focus on Sartre's early philosophical work, which dealt first with imagination and the emotions, then with the critique of Husserl's notion of a transcendental ego, and finally with systematic ontology presented in his best-known book, Being and Nothingness. In addition, since his preoccupation with ontological questions and especially with the meanings of ego, self, and consciousness endured throughout his career, other essays discuss these themes in light of later developments both in Sartre's own thought and in the phenomenological, hermeneutic, and analytic traditions.