Saints, heroes, Santa Clauses, whatever you may call them, Tracy Kidder has a knack for seeking them out.

Dr. Jim O’Connell, the physician who founded Boston’s Health Care for the Homeless Program, is the subject of Kidder’s latest book called, Rough Sleepers.

For three decades Dr. Jim, (or “Saint Jim,” as he is occasionally and lovingly called—and a term he doesn’t much like) makes outdoor house calls to the men and women living on Boston’s streets. The bed-down in alley ways, Church squares and throughout the city’s parks summer, spring, fall and winter. They sleep on tarps under overpasses, and on beds made of big box cardboard. They depend mostly on themselves, sometimes on each other, and occasionally on the kindness of strangers. But for many Rough Sleepers- a 19th-century British term for those who live outside- who know him, they depend on the nighttime heroics of their beloved Dr. Jim.

Jim O’Connell is a miracle worker much as Dr. Paul Farmer, the protagonist of Kidder’s book Mountains Beyond Mountains. Both men who made loaves into fishes, and a dollar out of ninety-nine cents, built hands-on healthcare for the masses from scratch.

Kidder followed alongside O’Connell for five years to write this book, through every kind of survival situation in good weather and bad, mostly at night while Dr. Jim tended to his flock by passing out first aid, socks, sandwiches, advice, and sometimes, a few bucks. Mostly he tried to get them inside to safety and sometimes hospitalization.

Kidder is a gifted writer, one of my absolute favorites for the way he so capably steps aside on the page and becomes virtually invisible to the reader, leaving only the story, its setting, and its characters to shine through. And shine they do, with awe-inspiring sacrifice, boundless empathy, and immeasurable courage.

I waited five years for this book to come out when I heard Kidder was writing it. It was well worth every second.