There is considerable controversy, both within and outside the field of psychiatry, regarding the boundaries of normal sadness and clinical depression. Furthermore, while there are frequent calls for a "pluralistic", comprehensive approach to understanding depression, few writers have tried to integrate insights from the spiritual, philosophical, and neurobiological literature. The author proposes that such a synthesis is possible, and that our understanding of ordinary sorrow and clinical depression is enriched by drawing from these disparate sources. In particular, a phenomenological analysis (...) of sorrow and depression reveals two overlapping but distinct "lifeworlds". These differ in the relational, temporal, dialectical, and intentional realms. Recent brain imaging studies are also beginning to reveal the neurobiological correlates of sorrow and depression. As we come to understand the neurobiology of these states, we may be able to correlate specific alterations in "neurocircuitry" with their phenomenological expressions. (shrink)