After taking on dead bodies in Stiff, Mary Roach 'tackles the afterlife' in Spook (2005). From reincarnation to séances, ectoplasm to ghostly possession of spell-checkers, Roach visits, researches and often skewers those connected with research into just what it is that happens to us when we die.
I didn't laugh out loud quite as often while reading this as I did with the earlier book, but there were definitely some very humorous moments (usually when Roach expresses her skepticism of the people she's consorting with, many of whom seem a bit, eh, off). Her footnoted asides are also a source of continuing amusement.
Whether it's weighing dying bodies to determine the weight of the soul, or locking people in boxes and exposing them to electromagnetic fields in order to bring on a ghost, Roach's travels and researches make for great stories, and she recounts them well. A good read.