There are ghosts in here. You can feel them in the peeling walls, the dirty floor tiles, the wooden pews, and the 100-year-old mahogany ark that holds the Torah scrolls. And if you close your eyes, you can see them. It's a Friday night in, say, 1925. Men walk to this synagogue dressed in gray suits, crisp white shirts, and neatly knotted ties. As they step through the arched front doors, they remove their handsome black fedoras to reveal their yarmulkes. In the Orthodox tradition, women enter separately through a side door. They are dressed plainly, in long skirts and prim blouses. Upstairs, where symbols of Judaism are painted on the walls of the sanctuary and a Star of David dangles from a chandelier, the men sit in the first set of pews while the women sit in their own section. "Shalom," says the rabbi from the elbow of the L-shaped room, and moonlight shines through the skylights as the service begins.

Open your eyes now inside Boston's oldest synagogue, the Vilna Shul on Beacon Hill, and it's easy to imagine a time when Stars of David adorned more than 50 synagogues around the city, alongside steeples and crosses. This was the Boston of another era, because the latter half of the 20th century saw once-thriving Jewish neighborhoods in Roxbury, Dorchester, Mattapan, and the West End disappear as Jews moved to the suburbs, leaving behind historic synagogues, some of which were converted into churches...