Although the listing here on this website shows the reading level to be 9-12 years of age, I am fifteen and I enjoyed this book immensely.
If you like the TV show, it's good to see how the Yu-Gi-Oh saga begun. This also shows a little of how to play the card game, which can seem confusing at first, but is simple after you learn how to play.
If you don't like the show, or if you think the show is simply childish craze (as I once had), this book totally contradicts your opinions.
Given the fact that it is targeted towards twelve-year-old boys, it is surprisingly morbid, what with Dark Yugi's shadow games.
This is a good read for ages 11+, I believe. Even adults may find it amusing.