I bought this book at Gen Con last week and have read the whole thing. jandrese is not entirely, totally wrong. Ewalt talks about coming back to gaming as an adult after not having gamed since he was a kid, and the way he talks about it is definitely like gaming was something he's ashamed to return to. He worries about what his friends will think of him for gaming, especially his girlfriend, and talks about his interest in his d&d game like its an unhealthy obsession. As he gets into his game he compares it to drug addiction. He worries that gamers are smelly and fat, he says he gained thirty pounds because he started gaming. He does talk about going to a couple conventions and a LARP, but definitely only as research for his book, not something he would be doing otherwise... it doesn't sound like his convention experiences were positive, especially not when he tried to wargame. As a gamer and someone who does go to cons like Gen Con to play RPGs and wargames I found his atittude pretty negative and condescending, definitely he comes across as an outsider who's moved on to real life looking back at gamers who never grew up. I don't think any gamer who read this book would walk away with a different feeling, though probably Ewalt thinks this perspective will sell non-gamers by trying to say "I have the same stereotypes as you!"
And for the history of games, the material here is pretty basic and short, because so much of the book is just about Ewalt personal experiences and his gaming group. If you're a non-gamer, this is probably a good book for you to get a basic introduction. If you game, I wouldn't bother. Ewalt comes out and says this at the beginning pretty much. But this is definitely a "going-native" fish out of water story, and no one who even thumbed through the book would think differently.