Almost done reading this as of today and here's what I have to say about it: Dang it is good. The second prequel to the Maze Runner series, the book details Thomas's story before he was sent into the maze. The book covers how the maze was built and the story behind it. It also answers some mysteries from the kill order like: what happened to Deedee. (No spoilers here). If you like the Maze Runner I highly recommend this book.
Don't know what the maze runner is? Learn more here: https://mazerunner.fandom.com/wiki/The_Maze_Runner_(Book)