THE CENTERS FOR Disease Control and Prevention estimates that one in 68 children in the US are on the autism spectrum, a number that stands in staggering contrast to a 1970 study that put the figure at one in 14,200. Some people believe we’re in the middle of an autism epidemic. But autism has always been part of the human experience, as journalist (and WIRED contributor) Steve Silberman shows in his new book,NeuroTribes: The Legacy of Autism and the Future of Neurodiversity. It’s only recently, he argues, that we have become properly aware of it.