New York ? Michael Henry Adams strolls along Lenox Avenue in the middle of Harlem. He stops to watch a worker from a nearby renovation scrape patches of cheap color from a mahogany hall mirror to reveal the brilliant red wood underneath. Once restored, the old mirror could fetch $400 or more.

“There are all kinds of entrepreneurial people trying to make a buck off the heritage and history of Harlem,” Adams says with a shake of his head before he walks away.

Adams, an architectural historian, sees Harlem’s houses, apartment buildings, churches and libraries as memories of the neighborhood’s defining role in American history — as home of Revolutionary War battles, the Harlem Renaissance, poet Langston Hughes and singer Ella Fitzgerald. To him, every stripped-out hall mirror, knocked-down chimney or gutted building heralds the demise of an American treasure.

His concerns have rarely been more relevant, as Harlem emerges from a half century of urban blight. Developers are knocking down crumbling office buildings, replacing them with modern constructions. National chains such as Marshalls and Starbucks are popping up along Harlem’s boulevards.

Young professionals looking for cheaper rents and good housing buys have moved from downtown, pushing up property values, while thousands of poorer Harlem residents have trouble keeping their homes from falling into neglect.

Caught in the middle

Caught in the middle, Adams says, are the architectural marvels that tell Harlem’s story — how it began as a Dutch colony called Nieuw Haarlem in the 17th century, came to house the country estates of aristocrats, gave birth to the Harlem Renaissance in the 1920s and was a center for jazz and night life in the 1930s and 1940s and suffered an urban decay that lasted into the 1960s and 1970s.

Adams has laid out his image of what Harlem was — and the template of what he thinks it should be — in an exhibit at the Museum of the City of New York, “Harlem, Lost and Found.” The show, which runs through Jan. 4, 2004, details the history and architecture of Harlem, from 1765 to today, with scale-model homes, clothing, sculptures and lush photographs by Paul Rocheleau.

Among the most evocative displays are items Adams has scooped up from trash heaps: rusted pieces of wrought iron fence, chipped balusters, a gold-painted chunk of plaster garland from the Audubon Theater, where Malcolm X was assassinated in 1965.

Childhood passion

Adams’ passion with Harlem dates to his childhood in Akron, Ohio. He remembers reading the catalog for the 1969 exhibit at the Metropolitan Museum of Art, “Harlem on My Mind,” marveling that the neighborhood’s stately buildings were populated by blacks.

He recalls such Harlem success stories as Striver’s Row, nine acres on 138th and 139th Streets, an oasis of intricately preserved row houses. They were was commissioned in 1891 — Roman-inspired, cream-colored brick in the middle block with brick and brownstone homes surrounding them, shrouded by elm and other trees whose leaves hang low over the streets in summer.

A house on 136th Street once belonged to Madam C.J. Walker, one of America’s first self-made women millionaires who made a fortune from hair-care products. The limestone and brick building with a small, decorative balcony on the top floor was designed by Vertner Woodson Tandy, the first black architect licensed in the state of New York. Adams calls Walker’s home Harlem’s last mansion; it was demolished in 1942 to make way for a public library.

Preserving past

Such losses make Adams bristle and push him to fight even harder to preserve Harlem’s past. He fights to keep entire buildings from being razed, and he fights to make sure that cornices on brownstones are painted the same color as the houses themselves.

He is angry that chimneys have been knocked off the Marion Apartments. Except for its roofing — six gables topped with finials that resemble the neck of a violin — it’s an otherwise uninspired building on St. Nicholas Avenue.

He is angry about Graham Court, a landmark building on Seventh Avenue. Regarded as Harlem’s most beautiful apartment building, it is eight stories of wrought-iron balconies and an intricate curling design on stately light gray stone. But the building was desecrated, Adams says, because most of its distinctive green, wooden window frames were replaced by gray plastic.