You Wouldn't Want to Be a Roman Gladiator is not for kids younger than 2nd or 3rd grade, I think, but it's a very informative and engrossing way to teach history to kids in the appropriate age bracket. The book does not shy away from telling readers exactly what gladiators did, and what they experienced with their own bodies, and the book is clear that gladiator fights were battles to the death. That point, by the way, is bluntly and, for a children's book, perhaps shockingly, reinforced in the end.
All that said, my niece liked the book a lot, and I have no doubt that she got something out of this. My nephew was alternately horrified by and engrossed in You Wouldn't Want to Be a Roman Gladiator. This book is a little "too old" for him, so I probably shouldn't have read it in front of him just yet, but I was impressed with how well this lengthy book captured and held even his still limited attention.