The main plot is about Greg Heffley's various misadventures. He tries to deal with family stuff, like his relationship with his brothers. And at school, he has all these typical kid problems, like trying to fit in and avoid getting into trouble.
The main themes include dealing with popularity. Greg wants to be popular but always seems to end up in embarrassing situations. It also has the theme of responsibility. He has to take responsibility for his actions, like when he gets into trouble at school or at home, and this is a part of his journey in growing up throughout the story.
In addition to the ones mentioned, there are teachers at school like Mr. Ira who play important roles. They are part of Greg's daily life at school and often contribute to the comical and sometimes difficult situations that Greg faces. For example, Mr. Ira might give Greg a hard time with schoolwork or discipline.
Sure is! Diary of a Wimpy Kid is a fictional novel that follows the adventures and daily life of the main character. The books have been loved by many young readers.