Because the book covers thousands of years, it sometimes reads less like a novel and more like a history textbook written in the first person. It is episodic by nature; a problem arises in one century, it is solved, and then we skip ahead fifty years. This can make the middle section feel like a slog if you aren't invested in the minute political details of the fictional kingdoms.
Polgara the Sorceress (1997) is the direct companion to Belgarath the Sorcerer . It’s a first-person memoir of Polgara, the beloved, stern, and powerful daughter of Belgarath. The novel spans over 3,000 years of her life, from her childhood in the Vale of Aldur to the events of The Malloreon . polgara the sorceress pdf
Start with Pawn of Prophecy . Come back to this only after the 10 main series books. Because the book covers thousands of years, it