The book was originally on FunBrain, but when it was adapted into a print book, Jeff Kinney decided to split it into a series.
The series has stayed on the New York Times Best Seller list for children's books for 41 weeks as of November 1, 2009.
The first book begins with an introduction to Greg Heffley and his middle school life. It takes place during his (presumably) sixth grade year. The book also explains the cheese touch early on. It is similar to the game of tag in which the person who touched the cheese had to get rid of it by touching someone else. In the first half of the book, events such as Halloween, learning to know how to wrestle, and acting in the play of The Wizard of Oz occur. During trick or treating, Greg and Rowley are ambushed by a group of teenagers. Then they take refuge at Greg's grandmother's house and taunt the teenagers from there by making sounds and faces at them. On Christmas day, it shows Greg getting very few presents that he would like. Rowley bought Greg a Big Wheel. Greg then throws a football at Rowley while he is riding the Big Wheel and Rowley breaks his arm. At school, Rowley is surrounded by girls that encourage him to get well which makes Greg mad. Later, he and Rowley join the Safety Patrol whose responsibility is to walk home morning kindergartners. However, Greg gets kicked off the Patrol for chasing Kindergartners with a worm. When Greg gets kicked off, Rowley starts to ignore Greg. Slowly, they begin drifting apart and Rowley starts hanging out with Collin Lee and when he went to Rowley's house, Greg retaliates by spending his night at Fregley's. That turns into a disaster as Fregley goes crazy and Greg runs away in the middle of the night. Nearing the end of the school year, Rowley's comic strip is entered into the school's newspaper. Greg tells Rowley to list him as the co-creator because it was his idea and joke punchline. Rowley then denies that Greg had anything to do with it. They get ready to fight but are then interrupted by the teenagers they taunted on Halloween. They showed up to pay them back and they force Rowley to eat the cheese, but Greg gets away by saying he's allergic to dairy products. The next day, Greg explains that he removed the cheese, but the way he worded it, it sounded like Greg touched the cheese. For the rest of the year, Greg was in seclusion from everyone else and he and Rowley became friends again.