“For decades, Knight Landesman, 67, had been a pillar of the international art scene, a man-about-town known from the galleries of Manhattan to the Art Basel fair in Switzerland for his primary-colored suits and deep connections in the industry. The brother of the renowned Broadway producer Rocco Landesman, who once served as the head of the National Endowment for the Arts, he started at Artforum in the 1980s and until Wednesday had run the magazine with his three co-publishers, Anthony Korner, Charles Guarino and Danielle McConnell.”