Inside an Upper East Side nursing home on a September Sunday, Mimi Weinstein, who organizes and leads a weekly worship service there, bounced from resident to resident. She handed out bulletins and greeted people by name while shaking a tambourine. Two dozen residents showed up for the service, filling the activity room. Weinstein’s husband, Jerry, sat down at a baby grand piano, the top propped up with a copy of Jonathan Franzen’s Freedom, and started playing worship songs.

When a volunteer ...

“I am the father and mother of my children,” said Regina, sitting on the ground of the straw hut she built herself and weaving a basket.

The family’s possessions hang on the wall: a plastic blue bowl, a pair of small sandals, a green bottle cap. A toddler plays behind Regina’s back. A baby squirms in her lap. It is midafternoon in Nakorio village in northeastern Kenya, and nobody has eaten today.

Last year, Regina’s husband left for Lake Turkana. Other men have also abandoned ...