A set of 8 books from the "Adventure! Discovery! Great Maze!" series, plus "Maze of Civilization," for a total of 9 books. "The Secret Treasure of the Dinosaur Kingdom" and "Chronos, the Time-Traveling Train," and "Maze of Civilization" do not have covers. The appendix section of "Great Yokai Battle" has been cut out and is missing. There are some folds, but I think they are still perfectly readable. I believe there are no missing pages or writing, but there may be some oversights. Please understand that these books have been read and used by children before purchasing. Immediate purchase is welcome!