It seems decidedly odd that after more than half a century of both research and clinical experience with autism spectrum disorders (ASDs), there continue to be arguments on the nature of autism. "Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition" ["DSM-5"; American Psychiatric Association (APA), 2013] has not helped in this connection. It abolished the subcategories of ASDs because it had become obvious that, as specified in both "Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition" ("DSM-IV") and "International Statistical Classification of Diseases, Tenth Revision" (ICD-10), they had not worked. One alternative would have been to seek to devise better specifications, but this was not done--perhaps because there was limited evidence on what would work better and because it was doubted that a new scheme would achieve general acceptance. On the other hand, it is generally assumed that ASDs will prove to be heterogeneous. It is already known that they differ in the genes involved (Rutter and Thapar, in press), and it is highly likely that they will also differ in other aspects of biology. So what is all the disagreement about? In this article, the author turns to four articles for analyses. These four articles are by leaders in this field.