I read this simple and little book many years. When I first knew it, I thougt it was a Siddharta Gautama's (the original Buda's name) mini biography. When I opened the book I saw the book was a work of fiction. In reality, Siddharta is not the Buda, but in the story, the authentic Buda appears as a character.
Anyway, the main character of the story, which himself is called Siddharta, tells Buda it won't need their teachings in order to achieve a better life, but is the life itself it provide's the means for learning. In this way, this could be seen as Buddhism critic . I enjoyed the book, and to know that Siddharta, after all the things he goes through, he's a happy man.