This set includes the first five books of The Heroes of Olympus series by Rick Riordan: The Lost Hero, The Son of Neptune, The Mark of Athena, The House of Hades, and The Blood of Olympus. These hardcover editions feature vibrant cover art and are a great addition for fans of mythology and adventure. The books show signs of use with some edge wear and slight page creasing, but all are intact and readable. Perfect for collectors or readers looking to dive into this popular series.