Between the year 1961, when President John F. Kennedy sent Green Berets to South Vietnam, and 2001, when the Twin Towers fell to terrorist attack, America changed. Assassinations and riots. Youth rebelling and drugs romanticized. Civil rights for Black people, for women, for gay people. Throughout that tumultuous period, American artists became renowned around the world. In an exhibition that showcases 55 artists—among them Andy Warhol, Mark Rothko, Louise Nevelson, Roy Lichtenstein, Claes Oldenburg, Cindy Sherman, and Kara Walker—80 works embody a time of rich and multifaceted artistry in America. —E.C.