Diary of A Wimpy Kid: The Last Straw is the third book in the series. The story line according to the back of the book states that Greg's dad has had enough and unless Greg can toughen up quick, it's off to military school for the summer. However, that didn't actually happen until about 80% through the book.
The book read like an actual kid's diary, with no overarching story to hold it together. But that was okay. It was the same obnoxious humor that made me (and everyone else) like the first two books. However, it was still funny and fresh and even though Greg can be totally annoying, I loved watching his flawed logic.
These books definitely appeal to all ages and the third installment especially felt more like a kid's book for adults than an actual kid's book. This probably isn't a book that I will push into the hands of my nephew, because what makes it so funny is Greg's complete inability to change.
Diary of A Wimpy Kid: Dog Days felt more like a kid's book. The story explored Greg's summer vacation, fights with best friends, and his relationship with his dad. It had a lot more substance to it than the third book, but it was still fun and funny and easy to read over a single cup of coffee.
I'll check out book five from the library one of these days, because even though these books are basically the same every time, they don't bore me yet. And for adults out there who like this series, check out the You Damn Kid! archives.