This is The Heroes of Olympus set. It includes the whole series plus a bonus book to the series. There is some wear on each book. The Demigod Diaries has a sticker inside (see picture). 1. The Lost Hero 2. The Son of Neptune 3. The Mark of Athena 4. The House of Hades 5. The Blood of Olympus 6. The Demigod Diaries