Lord of Light by Roger Zelazny
To describe the book in one sentece: I was confused as hell for like 80% of the book, but confusion caused by the structure of the book is also one of the strengths of the book. The bad part is that everyone have like 3-4 names and knowing who is who is hell. Overall the story itself is great, the world feels strange and interesting and it is exactly as long as it should be. If you like Indian mythology it is a must.