Prodromal features of the schizophrenia syndrome have been described for a century, and work in the past two decades has produced a substantial literature based on these features to identify individuals at increased risk for developing a psychotic disorder. Sometimes conceptualized as a "risk state" and sometimes as early manifestations of a "disorder," the work has been conducted with several related but different constructs. Early in the preparation of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) public comment was sought on the proposal to create a new disorder termed attenuated psychosis syndrome (APS), and a range of issues emerged that generated interesting and important controversies. In this review, these criticisms are fully discussed, the APS concept is explicated; data relating to reliability, validity, and treatment are updated; the heterogeneity of APS is considered; and alternative views of the construct are presented with an emphasis on developmental pattern with timing for primary and secondary prevention and early treatment. Areas of future research are identified, and a potential roadmap for inclusion in DSM-5.1 is traced.