Crisis apparitions were the founding evidence base of organised psychical research. Edmund Gurney, Frederic W. H. Myers, and Frank Podmore, all central figures of the newly founded Society for Psychical Research, spent the mid-1880s collecting first-person testimony of apparitions, over seven hundred cases in total, and published them in 1886 as Phantasms of the Living, a title chosen deliberately to distinguish these visions of the recently or currently dying from traditional ghost stories about the long dead. Their central argument was that many apparitions coincided closely, often within hours, with a real crisis, illness, accident, or death, happening to the person seen, at a distance the percipient could not have known about through ordinary means, and that this coincidence rate was too high to be chance alone.
The Society followed with a more systematic study, the Census of Hallucinations, conducted between 1889 and 1894 under Henry Sidgwick's chairmanship, canvassing roughly 17,000 respondents and finding 1,684 who reported having experienced a waking apparition; the report's authors compared this rate against the known death rate in the general population and argued the correspondence between apparitions and real deaths occurring around the same time exceeded what coincidence alone would predict.