Playing with Genre: Erleuchtung Roman

Siddhartha chronicles the journey of the title character from his adolescence into old age. The novel functions as a Bildungsroman, or a novel of formation.
Novels like The Catcher in the Rye and Great Expectations are examples of Bildungsromans, which all share a common layout in which the protagonist leaves his home, struggles to understand the world, and finally comes to terms with society, or the way the world works. The genre shares a lot of similarities across different literary traditions, but there are significant deviations as well. Siddhartha, then, follows the basics of the genre, but Hesse successfully wields it to reflect a different set of values.
The basic components of the Bildungsroman seem to be the path the young narrator takes from home (usually in the country) out into the world (arriving in a city), the people he encounters, including a mentor and a sexual partner, a realization that this new world is still flawed, and finally a return to the home, either understanding something new about the world, or learning to accept it.
In Siddhartha, Hesse plays with the conventions of the genre in order to show that importance of defining one's self over conforming to society. In the novel, Siddhartha follows the path of formation by leaving home, eventually getting to the city and living a different life there with Kamala and Kamaswami before understanding that he is no longer on the path he sought. By highlighting from the beginning Siddhartha's quest for personal enlightenment, rather than a confusion about society or the world as a whole, Hesse tells us that he sees this as the more important journey for people to take.
The conventions that he alters or eliminates are, importantly, a repressive home environment and family, and then the ultimate return home. Because the family is not emphasized, we see that Siddhartha is driven to leave more by his own desires, not just because he's a rebellious teenager. Finally reaching enlightenment, though, Siddhartha has no desire to cross the river and return home again. He realizes that life is over, even a completely different one. Hesse does not send Siddhartha back home because it's not important to his sense of Nirvana. Traditional Bildungsroman protagonists will arrive at home and fit more comfortably into society. Siddhartha, however, stays by the river, continuing to be a ferryman, helping others reach enlightenment as he has. Society is of no concern for him because he has transcended it and has learned to live beyond the life he had before.