I was moved by The relationship between the old man and the boy.
However, in my view, this only is not enough to make a book famous.
The old man is brave for fighting with the big fish and sharks. He is old while He does not wan to surrend to age.
While saying he is fighting with the fish, I would rather say He is fighting with time, with age.
In the end, I still do not get why this book is so famous.