Mary Roach: Spook – Science tackles the afterlife, 2006
Roach does a fun romp investigating claims of the supernatural: Reincarnation (even going to India to investigate a purported case), various "scientific" investigations of spritism, ghosts and other kookery from the Middle to the New Age. She manages to be somewhat open – at least in the beginning, before becoming scientific and debunking things without descending into the at times tiresom earnestness of full-time skeptics.
The best part of the book is the language and the many funny foonotes, full of quips like reporting on someone communicating with a dead "Chopin (who has, we learn, resumed composing following a brief stint decomposing)". She looks into people trying to weigh the soul (by measuring body weight loss as a person dies) and various echtoplasm claims (spooky white material produced by mediums, mostly turning out to be cheesecloth.) An interesting explanation for ghosts may be that they are caused by infrasound, which can be produced by fans and other electrical equipment and be detected only by a few people, who may experience unease and blurry sights in the corner of their eyes.
Anyway, fun summer reading.