Sale of the Week Is a $21,450,000 Town House Throughout his career as a developer, David Edelstein has had a knack for buying low and selling high, and he has done it again with the Upper East Side town house that he owned with his wife, Susan, at 122 East 70th Street. The five-story brick and limestone house, which they bought for $12.85 million in 2010, sold for $21.45 million, making it the biggest sale of the week, according to city records. Mr. Edelstein is the president of Tristar Capital and the developer of the W South Beach Hotel in Miami Beach, where he also owns a penthouse condominium. He started his career in the 1970s, canvassing buildings for a real estate management company by day and driving a cab by night. He bought his first building on the Upper East Side with a $15,000 loan. He has since teamed up with major New York real estate entities, including the Vornado Realty Trust and RFR Holding. The Edelsteins' purchase of the house in late 2010 caused a bit of a stir - at least among Upper East Side town house brokers. The house had been on the market for more than a year, with an asking price that started at $20.2 million and was eventually reduced to $14.9 million. Brokers who had nearby town houses listed upward of $25 million feared that the $12.85 million sale price would wreak havoc with property values in the neighborhood. But the large profit that the Edelsteins have turned has no doubt held such worries at bay. Michael Kafka, an executive vice president of Douglas Elliman Real Estate, represented the Edelsteins. He declined to comment on the sale. The listing describes the renovated town house as "perfect for private use or lavish entertaining," having been "redesigned and reimagined for modern living while maintaining the traditional elegance and beauty of its spaces." The house comes with an elevator, a garden, four terraces, south-facing rooms at the back that have floor-to-ceiling windows and glass doors, and six wood-burning fireplaces, including one carved out of alabaster to look like draped fabric (it was designed for the previous owners by Samuel Botero). The ground floor has a large kitchen and a family room. The parlor floor has a 30-foot living room that opens onto a terrace, as well as another kitchen and a large dining room with arched floor-to-ceiling windows. The three upper floors have three bedrooms, a wood-paneled library and a media room. The roof deck has a kitchenette, and the finished basement has a staff room, a laundry and a storage space. The house was bought under a limited-liability company; the buyers were represented by Elizabeth Sample and Brenda Powers of Sotheby's International Realty. Ms. Sample declined to comment on the deal.