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The Alexander Shepherd Memorial stands proudly, carefully groomed by three workers, a Pennsylvania Avenue fixture in front of the D.C. municipal building that was once his sole domain.

That was then.

Now, “Boss” Shepherd looks just as jazzed to be overseeing his new fiefdom—a pair of temporary buildings at the Blue Plains Waste Water Treatment Plant—despite the indignity of the barbecue grill resting on his memorial’s base.

This photographic point/counterpoint is one of many made by authors Paul K. Williams and T. Luke Young in Then & Now: Washington, D.C. For each of the District neighborhoods featured, Williams says, there’s a narrative behind the changing scene.

“The typical then-and-now book is usually based on architecture, what the building used to look like and what it looks like today,” he says. “We had fun working with the human aspect of it, getting the story behind the physical place.”

Williams came across many of the photographs in Then & Now while doing archival research for books on Greater U Street, Dupont Circle, and Logan Circle, among others. (Young took many of the book’s present-day equivalents.) The sepia-toned images might not have found a home in Williams’ prior work, but they’re far from second-rate. Most evocative are those pictures that depict D.C.’s shifting social history, from how and where children play to patterns of work on the Southwest waterfront. But Williams doesn’t document change alone: His juxtaposition of images of the corner of 7th and P Streets NW—one from the aftermath of the 1968 riots, one from today—reveals that where a corner store once smoldered, still nothing stands.

Williams moved to the District in 1991 after graduate studies in historic-preservation planning at Cornell. He spent five years running an Air Force program that provided grants for preservation before starting his own preservation-related business.

Then & Now is but a signpost on Williams’ journey to document the District: His book on the history of Georgetown University is going to press next week, and photo histories of Woodley Park and Cleveland Park are also in the pipeline. “I’m just going neighborhood by neighborhood,” Williams says. “I’m up to nine, but I could probably come up with 25 really easily that could support a book.” —Josh Levin