Fatherhood is a book by Bill Cosby. The National Fatherhood Institute supplied Homer with the book to help him grow into a better father. Homer did not read through the entire book, but he did sample random passages here and there as he sought to be a better father to Bart in the episode Saturdays of Thunder.
It can later be seen in a pile of books in the Simpsons' fireplace.
Fatherhood was an actual book, written by Cosby in 1986 and published by Penguin. It was released in paperback in 1987.