At 8:32am, Sunday, May 18, 1980, Mount St. Helens erupted in Washington State with the explosive force of more than 20 million tons of TNT. It remains the most deadly and economically destructive volcanic eruption in the history of the United States. When author Shirley Rosen first heard the news, her immediate thoughts were of her 83-year-old uncle, Harry Truman, who owned the 50-acre Mt. St. Helens Lodge resort on the shores of Spirit Lake. Harry was his given name, but if anyone asked he'd say, "Just call me Truman." Drawing from interviews and memories of working at Truman's lodge,...