A little off the top, some spirited sports commentary, neighborhood gossip and a bit of man-to-man advice on domestic affairs: it’s all there at the barbershop, an institution that plays a beloved and central role in the African American community. Increasingly, in recent years, the black barbershop owner has become an influential source of health advice too. Public health officials and researchers have been actively enlisting his help in an effort to narrow gaping disparities in healthcare access and uptake that put black men at a deep disadvantage compared with whites. And deputizing the barber—an already respected figure in many...