Kirk R. Johnson is a paleobotanist and the Sant Director of the Smithsonian's National Museum of Natural History in Washington, D.C. He is the host of two recent PBS series, Making North America?and The Great Yellowstone Thaw.?He has written ten books including Prehistoric Journey,?Cruisin' The Fossil Freeway,?and Ancient Wyoming.?Ray Troll is an artist who has illustrated ten books, including Cruisin' the Fossil Freeway,?Sharkabet, Rapture of the Deep,?and Planet Ocean.?He and his wife, Michelle, own and operate the Soho Coho Gallery in?Ketchikan, Alaska.