The Rivan Codex: Ancient Texts of the Belgariad and the Malloreon David Eddings

So you want to write a multivolume, bestselling epic fantasy? Here's the book to help you. 
The Rivan Codex
 was published to answer the many letters David and Leigh Eddings have received from students, teachers, and aspiring writers. It's a companion to the 12-book fantasy series comprised of The Belgariad (five books), The Malloreon (five books), 
Belgarath the Sorcerer
 and 
Polgara the Sorceress
. In David Eddings's words, 
The Rivan Codex
 "may give the student of our genre some insights into the creative process--something on the order of 'connect wire A to wire B. Warning! Do not connect wire A to wire C, because that will cause the whole thing to blow up in your face." This is a collection of the groundwork David and Leigh Eddings laid for the Belgariad and Malloreon series. On this firm foundation they imagined and built their world in book after book.
There's a fascinating introduction, a personal history of Belgarath the sorcerer, Holy Books, Gospels, Histories, King Anheg's diary, and an afterword. Footnotes tell how the authors used and changed these materials in writing the books. And of course, there are plenty of maps (the starting point for all epic fantasies). --Nona Vero