TLDR; old man is upset an 8 year old child doesn’t know the basics of World War Two.
The first Magic Treehouse book I recall reading was the one where they went to Pompeii when the volcano erupted. For some reason, to my memory (and to me now), that’s a totally normal thing. Makes sense that they went to the entire natural destruction of an ancient town (glazing over the fact that thousands of people burned to death). But when I saw that Mary Pope Osborne sent these two kids into Nazi occupied France… I was blown away. Like, what the hell, lady?
Ultimately, it was a very good book. A good way to “lightly” introduce WWII to kids. When you find out the real reason why Jack and Annie were parachuting into France a day before the D-Day landings, you’ll probably be a little teary eyed, especially once you see the cost it took on their friend.
The only issue I take with this book is some real error with Jack and his knowledge of WWII. I understand that Jack is, like, 8 years old. But there is a point where, once they magic treehouse travel through time to Glastonbury, England in 1944, he and Annie ask their friend, Teddy, when and where they are and he tells them just that and asks them what they know about the Nazis. Jack, knows the minimum basics about the Nazis. Pretty surprising for an 8 year old. But he doesn’t realize that they travelled back to WWII until Teddy tells them they are fighting the Nazis. If he knew the basics about the Nazis, he should’ve known exactly what was going on when Teddy said they were in England in 1944. My final thing I have to say along these lines, is that, if Jack knew the basics of the Nazis, if he knew WWII was a thing, then he ABSOLUTELY should have known that D-Day was June 6, 1944. He found out when some French resistance tells him they heard it in a secret radio broadcast from the allies.
Anyway. Good book, easy read.