One recent December, at age 53, John Kralik found his life at a terrible, frightening low: his small law firm was failing; he was struggling through a painful second divorce; he had grown distant from his two older children and was afraid he might lose contact with his young daughter; he was living in a tiny apartment where he froze in the winter and baked in the summer; he was 40 pounds overweight; his girlfriend had just broken up with him; and overall, his dearest life dreams—including hopes of upholding idealistic legal principles and of becoming a judge—seemed to have slipped beyond his reach.

Then, during a desperate walk in the hills on New Year’s Day, John was struck by the belief that his life might become at least tolerable if, instead of focusing on what he didn’t have, he could find some way to be grateful for what he had.

Inspired by a beautiful, simple note his ex-girlfriend had sent to thank him for his Christmas gift, John imagined that he might find a way to feel grateful by writing thank-you notes. To keep himself going, he set himself a goal—come what may—of writing 365 thank-you notes in the coming year.

One by one, day after day, he began to handwrite thank yous—for gifts or kindnesses he’d received from loved ones and coworkers, from past business associates and current foes, from college friends and doctors and store clerks and handymen and neighbors, and anyone, really, absolutely anyone, who’d done him a good turn, however large or small. Immediately after he’d sent his very first notes, significant and surprising benefits began to come John’s way—from financial gain to true friendship, from weight loss to inner peace. While John wrote his notes, the economy collapsed, the bank across the street from his office failed, but thank-you note by thank-you note, John’s whole life turned around.