Andrew Wyeth dies at 91. His portraits of America help us understand Frost and Wyeth’s friend, Hopper. Most of all they move us by evoking the beauty and terror of isolation. A&L aggregates obits. American loneliness, accompanying individualism, connects Natty Bumppo to Ishmael to Huck Finn; Wyeth’s art respects that vitality in toughness, the mundane, the daily.