This book clearly emphasizes negative symptoms. Several points of consensus emerge regarding the need for additional studies specifically designed to address their treatment response, given the traditional emphasis on positive symptoms in therapeutic trials. Indeed, convincing arguments are made for the need for longer duration of trials, longer washout duration, and sampling specific populations with predominantly negative symptoms. This book also reflects the disagreements on how direct effects on negative symptoms should be differentiated from indirect improvements of negative symptoms mediated by reduction in psychoses, improvement in extrapyramidal symptoms, or other indirect mechanisms. Indeed, although Buchanan and Carpenter call for studies including patients with deficit/primary negative symptoms, others point toward difficulties in distinguishing primary and secondary negative symptoms and in recruiting a sufficient number of such patients. The latter argue for the use of statistical techniques to disentangle direct versus indirect effects. The authors on both sides, who are probably the best suited to defend these opinions, present their positions very thoroughly, which provides an interesting debate that calls for the readers’ critical sense.