Though shy of publicity not of his own making, he was often in the news, announcing a project or one of his 200 lawsuits against rivals, tenants, banks or even friends, often in losing causes. Like it or not, he was a New York real estate mogul, along with Donald J. Trump, the Fisher brothers, Lewis Rudin, Leonard Litwin, the Milstein family, Bernard H. Mendik, Larry Silverstein and Harry B. Helmsley.
While he dropped out of New York University in the 1950s, Mr. Solow, who was self-taught in fine art appreciation, amassed one of the city’s notable private collections of Renaissance and modern art, with works by van Gogh, Joan Miró, Jean-Michel Basquiat, Balthus, Picasso, Matisse, Botticelli, Giacometti, Morris Louis and Mark Rothko, as well as Egyptian antiquities and African art.
He bought most of his art from dealers. But in 1973, he picked up a telephone in New York, called Sotheby’s auction house in London and waged a trans-Atlantic bidding war that won him Picasso’s 1909 Cubist “Femme Assise” (Seated Woman) for $800,000, a record price then for a Picasso. In 2016, Mr. Solow sold the painting, in a Sotheby’s auction, for $63.7 million.
Philippe de Montebello, the former director of the Metropolitan Museum of Art, called Mr. Solow’s collection eclectic and distinguished. Its astronomical value was hard to calculate. Like many aspects of his life, his art generated controversy. Crain’s New York Business reported in 2018 that his art was held by a nonprofit museum that received federal tax breaks despite not being open to the public.
Sometimes his publicity was quite positive. In 1984, Mr. Solow built a row of 11 connected five-story single-family townhouses on East 67th Street in Manhattan, between Second and Third Avenues. They all had elevators and shared a private common garden in the back. It was a creation that had rarely been seen in Manhattan since the 19th century.