This book is about a teenager named Greg Heffley, and this book is his diary. In this diary, The Third Wheel, Greg writes about how his school is having a Valentine Party so he wants to find a date. However, Greg is not so popular at school, and it's a challenge for him to find some girl quick. So Greg decides to ask Rowley for help. But eventually, the girl chose Rowley instead of Greg. This leads to more trouble between Rowley and Greg's friendship, and Greg is left alone without a date. I really enjoyed reading this book because it talks about middle school friendship a lot and I could totally relate to not only Greg, but other characters in this book too. I really recommend this book to people who like reading about friendship and love.