Gave this to my nephews after they were my ring bearers. The book is jut a simple one with drawn pictures and at one part talks about how the groom gave the ring bearers a watch that can go under water... but we didn't do this, so it was a little weird and awkward. Just be careful if you buy this book that you plan on doing the things in it to avoid weird questions. We had gotten them a different gift and felt it was odd to call out specifics like this. Oh well.
...but don't buy this book AND 10 Neat Things about Being a Flower Girl. It is the exact same book, same wording, etc., with only a few gender changes here and there. That wouldn't have been a problem except that my ring bearer and flower girl are siblings in the same household. Now I feel silly giving them identical books. As for this book on its own merits, there is no story to it. I thought it only "sort of" explained the ring bearer's role and didn't really make it sound fun.
If you love the idea of having a ring bearer in your wedding but are a bit apprehensive about his behavior, this book should help settle your nerves. Give it to your young man before the wedding day to help him understand the ceremony and take his special role in it seriously. When it's over, hell have this handsomely designed book as a keepsake.