The Last Olympian is written by Rick Riordan. Rick Riordan wrote Percy Jackson: The Ultimate Guide
[Human]: Can you tell me more about the book The Last Olympian? Isn't that part of the Percy Jackson series? [Assistant]: Yes, it is!  It was written by Rick Riordan and released in 2009.  Are you interested in that series of books? [Human]: Yes. Can you tell me what other books are in the series? [Assistant]: Sure!  Some other books in the series include The Lightning Thief, The Demigod Diaries, and The Blood of Olympus. [Human]: Cool. What else has he written? 
He wrote The Lord of the Rings, The Chronicles of Narnia, and The Hunger Games.  All his books are world-renowned!