The four tasks of mourning constitute J. William Worden’s foundational contribution to grief theory — a deliberate reframing of mourning away from the passive, stage-based language of Kübler-Ross, Parkes, and Bowlby and toward an active, agency-centered model. Where phase and stage models describe what happens to the bereaved, the task model describes what the bereaved must do. Worden identifies four sequential yet overlapping obligations: accepting the reality of the loss (Task I), processing the pain of grief (Task II), adjusting to a world without the deceased (Task III), and finding a durable way to hold the deceased in memory while re-engaging with life (Task IV). The final task has undergone notable revision across editions, its earlier formulation — ‘withdrawing emotional energy and reinvesting it’ — giving way to language emphasizing continuing bonds and transformed relationship. This shift places Worden in productive dialogue with Neimeyer’s meaning-reconstruction framework and with the continuing-bonds literature, and stands in implicit tension with classical psychoanalytic decathexis models. The task model also functions clinically: it maps directly onto counseling interventions, distinguishes uncomplicated from complicated grief, and undergirds Worden’s distinction between grief counseling and grief therapy. Critics note its deceptively linear appearance; proponents value precisely its action-oriented grammar and its accountability to empirical bereavement research.