Sidney Janis grew up in Buffalo,and moved to New York City in 1924, after his marriage. He began collecting in 1926 with the purchase of a Matisse. After a career writing about art, Janis opened his own gallery on 57th Street in 1948. There he exhibited first the abstract expressionists, including Pollock, deKooing, Gorky and Rothko, and later Pop artists. In 1967, Janis gave his private collection of 103 works to the Museum of Modern Art.
Jones, Alan and Laura de Coppet. The Art Dealers: The Powers Behind the Scene Tell How the Art World Really Works. New York, 1984:33-42