For some folks, having your life turned into an Oscar-winning movie would be a life-changing experience. But Leigh Anne and Sean Tuohy—the Memphis couple whose actions inspired Michael C. Lewis’ book The Blind Side and its subsequent hit-film adaptation—already had experienced that kind of amazing change. In their new memoir In a Heartbeat, they share how it came from changing the lives of others.

As a straightforward biography, In a Heartbeat describes the factors that shaped the Tuohys’ willingness to become surrogate parents for Michael Oher: Sean as a teenager depending on the kindness of friends after his father’s incapacitating stroke left the family with little money, and Leigh Anne observing her own mother extending generosity—and occasionally a place to stay—to a needy friend. They also continue the story of The Blind Side with what happened after Michael headed to Ole Miss University, and eventually to the NFL.

Mostly, however, it’s inspirational reading of the best kind. As Sean becomes a successful businessman, and the Tuohys’ wealth offers them opportunities to give, they initially feel paralyzed by where their money should go to do the most good. They settle on what they call the “Popcorn Theory”: You can’t do everything, but you can help the person who has popped up right in front of your face. In a Heartbeat becomes a powerfully effective call to realize that the opportunity to change a life is available every day, as long as you’re prepared to open your eyes and your heart.

Leigh Anne and Sean Tuohy booksigning @ Costco, 1818 S. 300 West, 801-401-1050, noon; @ The King’s English Bookshop, 1511 S. 1500 East, 801-484-9100, 4 p.m., July 17