She's out to prove that there's no such thing as choosing happiness.

Isadora Bentley follows the rules. Isadora Bentley likes things just so. Isadora Bentley believes that happiness is something that flat-out doesn't exist in her life—and never will.

As a university researcher, Isadora keeps to herself as much as possible. She avoids the students she's supposed to befriend and mentor. She stays away from her neighbors and lives her own quiet, organized life in her own quiet, organized apartment. And she will never get involved in a romantic relationship again—especially with another academic. It will be just Isadora and her research. Forever.

But on her thirtieth birthday, Isadora does something completely out of character. The young woman who never does anything "on a whim" makes an impulse purchase of a magazine featuring a silly article detailing "Thirty-One Ways to Be Happy"—which includes everything from smiling at...