Thousands of articles and blogs have been written theorizing about the complicated backstory of World of Warcraft. Over the years information has trickled out through quest texts, cut scenes, and tie-in novels and comics. Every player who cares about this aspect of the game has their favorite theories about the Titans or the Burning Legion or the Well of Eternity, and how all the pieces fit together. Now Blizzard has put much of the speculation to rest by publishing an official account of Warcraft lore.
It is surprising that Blizzard would decide to make a book like this because it ties their hands to a certain extent. They clearly plan to release many more expansions, but if they want to introduce another unexplored continent to Azeroth or new races they will have to explain why information about those places and peoples were omitted from the Warcraft Chronicle.
Personally, I find the cosmology and history of Azeroth as much or more interesting than the actual game play. It kills me whenever my character enters one of the beautifully rendered libraries in the game and none of the books are clickable. Nothing to do but go kill a dozen bears and bring their pelts back to the local quest giver to build my rep. If you love the lore then you will enjoy this book. I should mention that there is nothing in the book that will help you play the game. If you want to improve your DPS or down a raid boss you can find those tips on YouTube.