Rick Riordan wove a very exciting story in "The Maze of Bones", one that in my opinion is better than his Percy Jackson series. If he had written the entire series, it would have been amazing, but as things were it gradually went downhill. I was disappointed by Peter Lerangis' contributions to the series, and feel that the others, while enjoyable (particularly when Patrick Carman and Margaret Peterson Haddix are responsible), don't come close to Riordan's level of quality. He managed to mix in all of the teams in a fast-paced, adventurous chase to find the Cahill family's most carefully guarded secret. And, in my opinion, the various series-within-the-series dragged it out much too far. If Rick Riordan had written them all, the quantity of the books would have been much less, but the quality would have been much, much better.