Distress Tolerance occupies a distinctive structural position within the depth-psychology and clinical-psychology corpus represented in this library: it is simultaneously a discrete skill module within Dialectical Behavior Therapy and a broader capacity whose conceptual foundations reach into somatic, neurological, and developmental frameworks. In the DBT literature, as systematized by Scott, Distress Tolerance names the fourth module of skills training — the cluster of capacities that permits individuals to survive crisis without behavioral deterioration, principally through techniques of radical acceptance, self-soothing, distraction, and the TIPP protocol. This instrumental framing exists in productive tension with the more phenomenological accounts offered by Siegel, Ogden, and Price, for whom the underlying capacity is inseparable from the neurophysiological concept of the window of tolerance: the bandwidth of arousal within which integrative processing remains possible. Levine and Dayton situate the deficit in distress tolerance within trauma’s disruption of neuromodulation, linking low tolerance thresholds to the collapse of the body’s self-regulating capacities. Porges frames recovery of tolerance as contingent on cues of safety rather than volitional technique alone. The field thus divides between a skill-training model — in which tolerance is cultivable through deliberate practice — and a regulatory model — in which tolerance is a property of the nervous system that must be restored relationally and somatically before skills can take root.