I bought this because I read so many glowing reviews, but at the end of the day it wasn't for me.
1) A good number of the puzzles are map puzzles, involving tediously searching for matching coastlines and hunting for city names. Not my thing.
2) A good number of the puzzles are math puzzles, which are also not my thing.
3) A good number of the puzzles involve trawling the Internet for the names of Nazis and facts about their military strategies. (The Nazis are, obviously, portrayed as bad guys.) I did not find it personally fun to spend the whole experience researching various Nazis.
For players who like geography, math, military history, and a lot of research, this would probably be the puzzle book for you.