Several years ago, I acquired a recording of Sibelius’s fifth symphony. This is one of his best-known works, but the version I received was the original 1915 one rather than the revised 1919 version, which until fairly recently was the only recording ever heard. What I expected were minor changes in orchestration, with perhaps a few passages removed or extended here and there. What I got was the kind of shock you might feel if you met someone in the street you had known all your life and found that he was twenty centimeters taller than he was three weeks last Tuesday and that his hair had turned blue. When I cast a skeptical eye over newspaper, magazine, and television coverage of scientific topics, I often get much the same feeling.1