The Rosie Effect is a workplace drama romance novel written by Graeme Simsion. It is the sequel to The Rosie Project and continues the story of Don Tillman and Rosie Jarman. As they navigate the challenges of marriage and impending parenthood, Don's logical thinking and unconventional approach to life create humorous and heartwarming situations. This book explores themes of love, acceptance, and the importance of adapting to change.