This book is a great addition to the saga; a real added bonus for those who already love Eddings' work. Its wry humour and great storytelling style make it a definite page-turner, despite a few qualms I had with Belgaraths' little 'asides' to the reader - amusing to begin with, but a few of his quips fell short with me. However, overall, an extremely enjoyable read.
However, I must add a word of warning to potential readers out there. A lot of reviewers have been recommending Belgarath the Sorcerer as a good way to start on the Belgariad and Mallorean series - it IS a nice summary of the world Eddings has created but some people might want to avoid it until they have read the other series as this book reveals many of the plot-twists which, for me, made the Belgariad and Mallorean so enjoyable. Eddings' device of starting and ending this book with episodes from Garions' current life, set after Seeress of Kell, is a good idea but it means that a new reader will quickly find out what happens to the gang in the end - if you're the kind of person who flicks to the ends of books anyway then that's alright, but if you want to save the surprises for later then don't read this book yet! A friend of mine picked up Belgarath the Sorcerer before reading the other books and was disappointed that she then knew what was going to happen to Garion and his friends. Also, the world-building which came quite gradually in the Belgariad and Mallorean is now crammed into one book here, and I think many of the references to events in the other novels would be lost on new readers here, especially towards the end of this book when emphasis is heavily on the background of characters such as Silk, Barak and Garion.
Overall, a great book, but you'll get more out of it if you've read Eddings' previous works already!