How did creationism become a seemingly permanent obstacle to the teaching of evolution in the public schools of the United States? Glenn Branch, deputy director of the National Center for Science Education, will tell the tale, from the Scopes trial in the '20s, through the creation science movement of the '70s and the intelligent design movement of the '90s, to today's strategies to undermine the teaching of evolution. The resistance to evolution is constant, but the creationist strategies continue to evolve.