Angle of Repose (Penguin Twentieth-Century Classics) by Wallace Stegner. One of our contributors reminded me of this gem, saying “I'm not sure why a book set mostly in mining towns in the West during 1880s appealed to me, but it did. It is the best book I've read!” Crossing to Safety, also by Stegner, has appeared on our list previously, one of my all-time favorites, and I think a good "beach classic."