Hades: Lord of the Dead is undoubtedly the best of the Olympians series. I love how, instead of leaping around from myth to myth and story to story, O'Connor chose the story of Persephone to introduce us to Hades and his underground realm. This most likely has something to do with the fact that the story of Persephone and Hades is my favorite Greek myth, but also had something to do with the fact that it was the most cohesive story; the narrative flowed nicely and didn't confuse anyone by jumping around and introducing new characters or stories. I also love the twist O'Connor provided with the story of Persephone; I don't want to spoil anyone, but let's just say that her relationship with Hades was a bit more kosher than some versions of the tale that I've read!