I just started reading a translation of Sartre's L'Etre et La Neant (Being and Nothingness). I have to read it in order to full analyse Huis Clos (No Exit) also by Sartre. It's all for a ridiculous senior paper in English (HS). Basically, from what I've read so far in Being and Nothingness, I really don't understand where Sartre's theory of existentialism differs from other philosophers' definitions. So can anyone help me with Sartre's belief or definition of existentialism?