The Rule Book is a 2024 New York Times bestselling novel by Sarah Adams. It's a second-chance romance and enemies-to-lovers story about college exes, Nora Mackenzie and Derek Pender, who reunite years later. Nora is a rising sports agent in a male-dominated field, and Derek is a famous NFL tight end. Nora's career rests on Derek, making their professional relationship complicated by their past romance.