Our perception of autism spectrum disorder has evolved over time. Sixty years ago, the condition was nothing more than an unrecognized developmental delay generally lumped in with intellectual disabilities. Today it is recognized as an independent neurologically based disorder of significance, a major public health issue, and a topic of much research. Researchers have struggled to find a cause for the disorder without great success. Despite this difficulty, research continues in ever more sophisticated directions. Numerous treatments have been developed that help children with autism spectrum disorder to maximize their potential to learn and become socially fluent, no matter how strong their impairments may be. There is cause for hope.