The Dragon Bone Chair by Tad Williams
I stumbled upon this book in The Fantasy Book Club on Facebook and followed the links to see what I could learn about it. One of them brought me to a Wikipedia page for the book which has a lot of interesting information. Check it out.
The Dragonbone Chair is a fantasy novel (written in 1988) by American writer Tad Williams, the first in his Memory, Sorrow, and Thorn trilogy. The saga follows a young man named Simon as he is caught up in an epic adventure. You can get it at Amazon.