"Diary of a Wimpy Kid" is a comedic children's book written and illustrated by Jeff Kinney. The story is presented in the form of a diary written by the main character, Greg Heffley, a middle-school student. The diary entries are accompanied by cartoon-style illustrations. The book humorously explores the challenges and experiences of Greg as he navigates the ups and downs of school life, friendships, and family relationships. The relatable and humorous storytelling style has made the book a popular choice among young readers.