“It's supplemental, and is 'written' by Belgarath after the Malloreon series takes place. It basically gives context to all the legends and histories talked about during the Belgraid and Mallorean series. A lot of the commentary is best appreciated after you've read the all the other books in the series. (It's also fun to read Polgara the Sorceress after you've read this book.)”
“This book is confusing as to where it places in the series The Belgariad. Some sites list it as Book 6 (http://www.fantasticfiction.co.uk/e/david-eddings/), Others call it a Prequel to the series (http://en.wikipedia.org/wiki/Belgarath_the_Sorcerer). ”
