In 1965, the eccentric loner Ray Johnson was dubbed “New York’s most famous unknown artist.” The source of that moniker is also unknown, but the meaning is clear. After graduating from the experimental Black Mountain College in 1948, Johnson moved to New York and founded the New York Correspondence School, a social network that encouraged artists and writers to share their work by shipping it around the country. Johnson called this “mail art,” and it inspired his 1950s collages. Those works—which feature cardboard cutouts, newspaper clippings, hand-drawn cartoons, annotations, and his own name in large letters—served as inspiration for the Pop Art, Fluxus, and Conceptual Art movements. Highlighting Johnson’s belief that art requires cooperation, this exhibition displays his collages alongside the work of his collaborators: archivist Bill Wilson, publisher Dick Higgins, computer scientist Toby Spiselman, and artists Karl Wirsum and Robert Warner. —J.D.