Anxiety
The philosopher Søren Kierkegaard, in "The Concept of Anxiety" (1844), described anxiety or dread associated with the "dizziness of freedom" and suggested the possibility for positive resolution of anxiety through the self-conscious exercise of responsibility and choosing. In "Art and Artist" (1932), the psychologist Otto Rank wrote that the psychological trauma of birth was the pre-eminent human symbol of existential anxiety and encompasses the creative person's simultaneous fear of – and desire for – separation, individuation, and differentiation.
Darwin's Dangerous Idea
Dennett's previous book was "Consciousness Explained" (1991). Dennett noted discomfort with Darwinism among not only lay people but also even academics and decided it was time to write a book dealing with the subject. "Darwin's Dangerous Idea" is not meant to be a work of science, but rather an interdisciplinary book; Dennett admits that he does not understand all of the scientific details himself. He goes into a moderate level of detail, but leaves it for the reader to go into greater depth if desired, providing references to this end.