Searching for the elusive answer to a persistent question concerning the seeming gullibility of my fellow Americans—namely, why did 42 percent of adults surveyed this spring by Gallup say they believe that God created humans in their present form less than 10,000 years ago?—I recently found myself in the office of Ken Ham, the born-again Barnum behind Kentucky’s $35 million Creation Museum, debating a separate but related question, one whose existence I had not previously recognized but which became for me a source of instant paleontological delight: How could dinosaurs have coexisted with other animals within the teeming confines of Noah’s Ark?