In a single move, Leonard Lauder has helped a New York museum become a leader in Cubism. The chairman emeritus of The Estee Lauder Companies will give The Metropolitan Museum of Art his collection of 78 works by Pablo Picasso, Georges Braque, Juan Gris and Fernand Léger, believed to be one of the foremost collections of Cubism in the world. The Met announced the donation, described as a billion-dollar gift by The New York TImes, after the museum board approved it at a meeting on Tuesday....