These three genres come together in Siddhartha as Siddhartha’s life (biography) is devoted to attaining (quest) enlightenment (philosophical literature). Let’s break it down further for you. The novel follows the course of Siddhartha’s life, which makes it a biography. However, his life is directed towards one goal, which makes the story of his life a quest. Lastly, since Siddhartha’s goal is enlightenment, the novel can be considered philosophical literature, as he rejects various philosophies on his way to enlightenment.