An excerpt from my upcoming book on ghost investigation: "The quantity and variety of alleged spirit images has exploded over the years, but the quality of the evidence remains as disappointingly ambiguous as ever. Some are shadowy, human-like figures; others are flash reflections of light appearing as round white spots dubbed “orbs”. Some ghosts are reported to look and act exactly like living, real people, with their true nature only being revealed when they suddenly vanish or walk through a wall. If those accounts are to be credited, then logically and theoretically there could be tens of millions of ghost photos that are not recognized as such—strangers in crowds or backgrounds in public areas could presumably include ghosts. If these spirits are visually indistinguishable from ordinary people as some eyewitnesses claim, then any photo which contains one or more people whose identity (and therefore status as alive or dead) is not conclusively known could include a ghost. I’m not suggesting this is the case, of course, but merely noting the practical complications that this view of ghosts implies..." You can find more on me and my work with a search for "Benjamin Radford" (not "Ben Radford") on Vimeo.