A never ending story poetic

After reading the very good The first fifteen lives of Harry August, I attacked this work written much earlier. The story is quite different here as Jeff, the hero who keeps reliving his life between the 60 and 88 is alone and trying many tricks to improve his life and the experience he withdraws.
Besides a smooth and pleasant writing, the book exudes a form of poetry and interrogation of humanity. Jeff asks much and poses a peaceful view of the world. While the book is primarily a book oscillating between fantasy and science fiction, but in my opinion a major book in the fantasy literature /