Diary of a Wimpy Kid: No Brainer is a part of the popular Diary of a Wimpy Kid series by Jeff Kinney. This book includes a series of cartoons, funny anecdotes, and Greg Heffley’s reflections on his life. It focuses on Greg navigating through various humorous and awkward situations, often revolving around his family, friends, and school. As with the rest of the series, the book combines humor with themes of growing up, facing challenges, and dealing with personal quirks.