The second book in the Sword of Truth series is Stone of Tears.
This was this first book I originally read of this series, the one that got me hooked and still after reading all of them many, many times I think it is one of the best. It really develops the characters further...it gets to the heart of them one might say.
One of my favourite things about this particular universe is that everything and everyone in it has a purpose that eventually comes to pass and the smallest actions that seem irrelevant at the time make these huge ripples chapters later. Or in some cases books later.
So it really does feel like it requires a second walk through once you get all the way to the end because you have the questions about whether or not things happened the way you think they happened.