In 1864, amid headline-grabbing heresy trials, members of the British Association for the Advancement of Science were asked to sign a declaration affirming that science and scripture were in agreement. Many criticized the new test of orthodoxy; nine decided that collaborative action was required. The X Club tells their story. These six ambitious professionals and three wealthy amateurs--J. D. Hooker, T. H. Huxley, John Tyndall, John...