What is it that happens when the dead appear, when ghosts manifest? Beyond the variety of contexts, eras and approaches presented here, this volume considers ghosts not only as things that are believed in (or not), but also – and above all – as things that happen, as events. By the institutions they set in motion, the doubts they stir, or the solutions they inspire, these events generate solidarity, rekindle old conflicts, and define the borders of communities; in short, they force the living to recompose their world anew. Documenting an apparition invites us not only to ask what appears – that is, the forms that ghosts may take around the world – but also what it is that the apparitions themselves make appear; what is made visible as a result of a ghost’s manifestation.