This book is a 10 because it can be read on both a literal and a symbolic level.
I adore this book. I love how it can be used with younger children as a simple adventure story about survival at sea with wild animals. I love how it can be used with teens to explore the importance of storytelling and coming-of-age stories between cultures. I love how it can be used with adults to explore the very fundamentals of religion and faith.
I remember staring for a LONG TIME at the line that (in my opinion) forms the crux of the book: "And so it goes with God." Even someone with a high level of education such as myself had to allow the gravity of that statement to sink in before I could truly understand it. Let's look at the entire section in its entirety. It happens as Pi is explaining his story to the Japanese men from the Maritime Department. The conversation goes as follows:
Pi Patel: "So tell me, since it makes no factual difference to you and you cant' prove the question either way, which story do you prefer? Which is the better story, the story with the animals or the story without animals?
Mr. Okamoto: "That is an interesting question..."
Mr. Chiba: "The story with the animals."
Mr. Okamoto: "Yes. The story with animals is the better story."
Pi Patel: "Thank you. And so it goes with God."
In other words, Pi believes that God tells a different story to different people depending on the belief system that they will accept in the culture that will accept it. Pi believes that all God's are actually the "One God" which is similar to the very New Age concept of "All One." Interestingly, Pi refuses to give "his" one God a definite label and uses all three from the world's three main religions: Hinduism, Islam, and Christianity. ("Jesus, Mary, Muhammad and Vishnu." Interesting also that Pi includes the Mother of Jesus there as well.)
In my opinion, the most interesting thing about this idea is that the three religions believe themselves to be mutually exclusive! ... Therefore, no one who is a true member of ANY of those three religions is "allowed" to believe in the other two! Pi, therefore, has come up with an entirely new and universal concept.
So, yes, this book is a 10. No doubt.