Peter Max, the German-born American artist whose swirling, vivid imagery came to define the optimism of the 1960s "flower power" movement, died on Monday at the age of 88. His son Adam confirmed the death in a written statement, saying the family would miss "the father we knew and loved" above all else. Over a prolific career spanning more than six decades, Max served as official artist for events including the Olympics and the Super Bowl, and his work appeared on everything from US postage stamps to a Norwegian Cruise Line ship — making him one of the most widely seen commercial artists of the 20th century.