Sin War, Book One: Birthright
We have the excerpt of Diablo: The Sin War, book one: Birthright available at the Diablo pocketbooks Excerpts section. The pocketbook – by Richard A. Knaak – will be released on October 2006 and contains 336 pages. You can pre-order it at the Pocketbooks section
Check out the Sin War lore from Diablo 1 Game Manual.