Our dogs come into our lives as “just the family pet,” but before we know it they become drinking buddies and fuzzy shrinks, playmates and Cheerios-munching vacuum cleaners, alarm clocks and sleeping partners. And, in their mys­terious and muttish ways, our dogs become our teachers.

When Dana Jennings and his son were both seriously ill—Dana with prostate cancer and his son with liver failure—their twelve-year-old miniature poodle Bijou became even more than a pet and teacher. She became a healing presence in their lives. After all, when you’re recovering from radical surgery and your life is uncertain, there’s no better medicine than a  twenty-three-pound pooch who lives by the motto that it’s always best to play, even when you’re old and creaky, even when you’re sick and frightened.

In telling Bijou’s tale in all of its funny, touching, and neurotic glory, Jennings is telling the story of every dog that has ever blessed our lives. The perfect gift for animal lovers, What a Difference a Dog Makes is a narrative ode to our canine guardian angels.

DANA JENNINGS is currently a feature writer at the New York Times and writes a popular weekly column about coping with prostate cancer and its aftermath for the Times’s “Well” blog. He is the author of five previous books, most recently Sing Me Back Home. He lives with his family in Upper Montclair, New Jersey.