Now in paperback - Diary of a Wimpy Kid: Dog Days is the fourth mega-selling installment in the hilarious Diary of a Wimpy Kid series. Greg's mom has a vision of 'family togetherness' that really doesn't sound a whole lot of fun. But there's a brand-new addition to the Heffley family to contend with and it looks like Greg might be outnumbered. It could be a real dog of a summer.