We outline a crisis in clinical description, in which atheoretical categorical descriptors, as in the Diagnostic and Statistical Manual of Mental Disorders (DSM), has turned focus away from the obvious: evolved major adaptive systems. Adaptive systems, at the core of a medical review of systems (ROS), allow models of pathology to be layered over an understanding of systems as they normally function. We argue that clinical psychology and psychiatry would develop more programmatically by incorporating 5 systems evolved for adaptation to the external environment: reality modeling for action, short-term danger detection, long-term cost-benefit projection, resource acquisition, and agenda protection. These systems, although not exhaustive, coincide with great historical issues in psychology, psychopathology, and individual differences. Readers of this journal should be interested in this approach because personality is seen as a relatively stable property of these systems. Thus, an essential starting point in ROS-based clinical description involves personality assessment. But this approach also places demands on scientist-practitioners to integrate across sciences. An ROS promotes theories that are (a) compositional, answering the question: What elements comprise the system?; (b) dynamic, answering: How do the elements and other systems interact?; and (c) developmental: How do systems change over time? The proposed ROS corresponds well with the National Institute of Mental Health's recent research domain criteria (RDoC) approach. We urge that in the RDoC approach, measurement variables should be treated as falsifiable and theory-laden markers, not unfalsifiable criteria. We argue that our proposed ROS promotes integration across sciences, rather than fostering the isolation of sciences allowed by atheoretical observation terms, as in the DSM.