"Being and Nothingness" is a philosophical work by Jean-Paul Sartre that explores the nature of existence. Sartre distinguishes between "being-for-itself," which refers to conscious beings like humans, and "being-in-itself," which describes objects that lack consciousness. This distinction highlights how humans create meaning in a world that is otherwise indifferent. The book also delves into the concept of existentialism, emphasizing that individuals are responsible for defining their own essence through choices and actions. Sartre argues that this freedom can be both empowering and burdensome, as it forces people to confront the reality of their existence and the weight of their decisions.