The Dragon Reborn by Robert Jordan

I particularly enjoyed how this book brought all its characters together for the climax in Tear. As the story wends its way on, I find myself wanting most to know about the back history of the world. Why is there a taint on saidin (the male half of the One Power)? Can this taint be cured? I enjoyed watching Nynaeve, Elayne, and Egwene team up to hunt the Black Ajah.