A cosmetic surgeon seeking a comfortable space for his patients to convalesce, a national foundation looking to relocate its headquarters, and a house-hunting Modern artist are among the prospective owners of the marble mansion on Riverside Drive at 107th Street.

The free-standing landmark, purchased by a Columbia University law professor for $325,000 in 1979, is on the market for $29 million. If it goes for that asking price, which was recently reduced from $31 million, the townhouse will be far-and-away Manhattan’s most expensive residence to be sold above 96th Street, real estate brokers say.

It has thrice changed hands since 1909, when it was built for Morris Schinasi, a Turkish émigré who made his fortune selling strong Turkish tobacco stateside. After Schinasi’s death in 1928, the property served as home base for an elite girls’ school and, later, a daycare center, before being sold to its current owner, Hans Smit.

“You live on a scale that’s very hard to achieve in New York — in spacious rooms, with total privacy” Mr. Smit, 79, said. “I was smart. I lived like a king in France on a Columbia law professor’s salary.” He said he was not surprised by the property’s exponential appreciation.

The Schinasi mansion, as it is still known, is one of Manhattan’s few remaining non-attached homes, architectural historians say. While the building’s exterior is French Renaissance in style, the interior reflects European and Oriental influences. It boasts wood and plaster wall and door embellishments, stained-glass windows, marble mosaics, and ceiling carvings and murals. One recurring design element is the pineapple, a symbol of hospitality for centuries. Pineapple ornaments adorn the banister of the grand, five-foot-wide sculpted oak staircase, the molding in the front parlor room, and the metal hearth of the ground-floor fireplace.

“It is a rare survivor on Riverside Drive, which was once built up with mansions and townhouses,” an architectural historian, Charles Lockwood, said. “What’s ironic is that these grand houses lasted only a generation, and then they were down.” Mr. Lockwood, the author of “Bricks and Brownstone,” a book about New York City townhouses, said these turn-of-the-century homes, started being demolished in the 1910s and 1920s. They were supplanted by larger, multi-family apartment buildings that are now staples of Riverside Drive.

There are 12 bedrooms, eight bathrooms, five kitchens, a light-infused fourth-floor studio apartment, a 3,500 square-foot garden, and even a closed-off tunnel that provided the Schinasi family access to Riverside Park across the street.

Mr. Smit, who hails from Holland, spotted the unusual residence while riding his bicycle nearly 30 years ago. Soon thereafter, he purchased the university-owned property, and moved in with his wife and two children. His adult son now lives in the home with his family. Mr. Smit still lives there when he is not at his home in upstate New York, or his Chateau in Burgundy, France.

The 12,000-square-foot home on Riverside Drive retains most of its original details, in addition to more recent accents like frosted-glass interior doors, marquis lights around the bathroom mirror, a ping-pong table, and a framed poster celebrating the rapper Eminem.

The asking price makes it doubtful that the place will be scooped up by another academic. It will more likely to be the plastic surgeon, the foundation, the artist, or a fund manager who’s also said to be interested in purchasing the manse, on the market since May. “It could be any one of the above,” one of the listing brokers, Diane Abrams, a sales agent with Brown Harris Stevens, said. “It could be a family. More people are open to living in a townhouse because the city seems safer now. For a while, people only wanted to live in a building with a doorman.”

Although some city brokers said the price sounded high, even for such a unique product, a senior vice president at Prudential Douglas Elliman, Nancy Weaver, said Mr. Smit might get what he’s asking for, or close to it. Ms. Weaver, who specializes in townhouses, said buyers are willing to pay a premium to be close to Columbia University, where housing stock is scare. “I wouldn’t knock the price,” she said. “Somebody might be willing to pay for it. You can’t predict this market, which is the highest it has ever been.”