Cherubs danced at the feet of muses as they plucked lyres on the domed ceiling of the old Steinway Hall on West 57th Street inManhattan. Their joy was reflected in the face of Marci Clark, who stood below them last week, expounding on the grandeur of the 91-year-old room.

The lot at 626 First Avenue, highlighted in red, superimposed on part of an 1865 map of the city.
The lot at 626 First Avenue, highlighted in red, superimposed on part of an 1865 map of the city. - Ms. Clark was hired as a marketing manager at JDS in 2013, and has quickly become one of the firm’s leaders. As soon as JDS considers acquiring a property, she heads to the archives at the Municipal Building, the Avery Architectural & Fine Arts Library at Columbia or wherever else she might turn up tidbits, to start developing a case for or against the project. Even buildings with no deep connection to the past can reveal secrets, such as 626 First Avenue. There, a former Consolidated Edison site is becoming home to 800 units in a pair of cantilevered towers joined by a skybridge. Ms. Clark found old maps showing that the property was once in the East River, which not only informed its foundation work but could also be seen as an echo of the pool that will exist atop the skybridge, 29 stories over Manhattan, and the river below.   © DAVID RUMSEY HISTORICAL MAP COLLECTION

“Done in the neo-Classical style, with marble columns, pilasters and cornice in a range of hues, this double-height octagonal space was the work of Walter L. Hopkins, who did some of Warren & Wetmore’s most distinguished work,” Ms. Clark explained, referring to the building’s architects. “The painting is believed to be mimicking the 18th-century Austrian painter Angelica Kauffman.”

As an architectural historian, Ms. Clark, 30, has studied buildings throughout New York City in pursuit of her doctorate. Yet her research at Steinway Hall has a very different end: selling apartments. As she spoke, buzz saws and blowtorches growled in the background, preparing the foundations for a 1,428-foot tower to rise from what was once one of the world’s finest piano shops.

Just over two years ago, Ms. Clark traded her mortarboard for a hard hat to work in the marketing department of JDS Development Group, where she is now a director. Her job involves putting together sales brochures, managing brokers and publicizing projects, but she prefers to spend her time in libraries and the dusty archives of architectural firms. There she unearths the blueprints, photos, maps and documents that guide JDS projects, whether or not they involve historical buildings. Old topographies might lead to better engineering; a salvaged grille could become a motif in a new kitchen.

“It’s not just a token gesture or marketing ploy,” Ms. Clark said. “It offers information to our designers and brokers on what to do with the projects, with the interiors and detailing. It’s a means of inspiration.”

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