Loss occupies a foundational position across the depth-psychology corpus, functioning simultaneously as clinical object, existential constant, and developmental catalyst. The literature divides broadly into two traditions. The first, anchored by Bowlby’s attachment-theoretical trilogy, treats loss as the disruption of affectional bonds and tracks its consequences through empirically grounded phases of mourning — numbness, yearning, disorganization, and reorganization — correlating early bereavement with depression, compulsive self-reliance, and dependent personality organization in adult life. Bowlby insists that instinctual equipment presupposes loss to be retrievable, rendering anger and protest intelligible biological responses rather than pathological ones. The second tradition, represented by Hollis, Neimeyer, and the Adult Children of Alcoholics literature, treats loss as cumulative and often pre-symbolic: shame, neglect, and relational failure are themselves losses of selfhood, carried silently into adult life as unexpressed grief. Here loss becomes not merely a discrete event but the medium through which identity is deformed and, potentially, recovered. Neimeyer’s constructivist contribution foregrounds meaning reconstruction as the adaptive task following major loss, while Worden systematizes clinical intervention through task-based models. A persistent tension runs through the corpus between loss as pathogen — the precipitant of depression and complicated grief — and loss as transformative crucible, the necessary disorientation through which genuine individuation and posttraumatic growth become possible.