Billerbeck (What a Girl Wants) delves into the science of happiness in this winsome romance. Happiness expert and college lecturer Maggie McGuire has hit a funk after a devastating breakup and now hides away from the world with gelato and romantic movies. To cheer Maggie up, her friends surprise her with a week-long singles cruise—and little does Maggie know that they have also set her up as the cruise's keynote speaker. While moping about the ship, she bumps into Sam Wellington, a Silicon Valley investor who challenges Maggie's academic research into happiness. After her friends' plan is revealed and Maggie begins planning her speech, she oscillates between trying to get out of her funk and wanting to continue to drown her sorrows in more ice cream. As Maggie confronts the possibility that her own research could be inaccurate, Sam's criticism of her work begins to appear more level-headed and her feelings toward him begin to grow. Despite the happy ending that feels inevitable throughout the book, Maggie never truly investigates her depressive thinking. Billerbeck's characters are flat and the faith elements are slim, but the sweet will-they-or-won't-they of Sam and Maggie's courtship will please readers looking for an unchallenging romance. (May)