This Upper West Side townhouse offers opulence in this world — and a longtime relationship with the otherworldly. 

The American Society for Psychical Research, a 138-year-old nonprofit committed to studying “extraordinary or as yet unexplained phenomena,” has put its tony headquarters on the market for $15 million.

Founded in 1885, the ASPR claims to be “the oldest psychical research organization in the United States” on its website, where it explains its focus on answering such questions as “How is mind related to matter, energy, space and time? In what unexplained ways do we interconnect with the universe and each other?” 

The group names a number of intellectuals and inventors among its alumni, including Chester Carlson, who invented Xerox, the dream researcher Montague Ullman and the quantum physicist David Bohm. Sigmund Freud and Carl Jung, the group notes, “were honorary members.”

As the group continues to explore such heady concepts, it’s sure of one thing: It wishes to part with the luxurious address. The current listing is not the ASPR’s first but second attempt to offload the 10,000-square-foot townhouse, Crain’s reported. In 2019, the Society first tried to sell the 18-room property for $18 million through Sotheby’s International Realty.

Now, Compass agents Charlie Attias, Alexandra Loeb and David Attias have the 5 W. 73rd St. listing for the reduced $15 million. 

Located across the street from the Dakota, the Beaux-Arts property boasts prewar details throughout, including nine original fireplaces — all imported from Italy — the original circular staircase framed by a roof skylight, an inlaid marble floor and a red brick and limestone facade. The property is 20 feet wide, and was designed by the architectural firm Welch, Smith and Provot, also credited with Fifth Avenue’s Duke-Semans Mansion.