This essay raises some questions concerning the method and conceptual structure of Sartre's Being and Nothingness. Three substantially different types of interpretation of this text have been put forward. One of the main issues separating the three interpretative strategies is the relationship that they each establish between Sartre's three fundamental concepts: consciousness, nothingness and freedom—each of which can be seen to play the fundamental role in the argument. It therefore seems crucial for any interpretation of Being and Nothingness to determine the exact relationship between these terms. However, Being and Nothingness presents a hybrid argument that interweaves metaphysical deduction, phenomenological description and moral-existential argument in a way that makes it almost impossible to decide which of the strands of the argument should be seen to dominate the others. It is therefore perhaps equally difficult to ascertain which of its principal concepts has the most central place in the system. One could therefore argue that a reading of Being and Nothingness should aim to account for (rather than dismiss) the hybridity of the argument and then seek to assign relative functions to its different strands. The following remarks are intended as a step in that direction.