The best-selling author of "Stiff: The Curious Lives of Human Cadavers" now trains her considerable wit and curiosity on the human soul. What happens when we die? Does the light just go out and that's that the million-year nap? Or will some part of my personality, my me-ness persist? What will that feel like? What will I do all day? Is there a place to plug in my lap-top?" In an attempt to find out, Mary Roach brings her tireless curiosity to bear on an array of contemporary and historical soul-searchers: scientists, schemers, engineers, mediums, all trying to prove (or disprove) that life goes on after we die. She begins the journey in rural India with a reincarnation researcher and ends up in a University of Virginia operating room where cardiologists have installed equipment near the ceiling to study out-of-body near-death experiences. Along the way, she enrolls in an English medium school, gets electromagnetically haunted at a university in Ontario, and visits a Duke University professor with a plan to weigh the consciousness of a leech. Her historical wanderings unearth soul-seeking philosophers who rummaged through cadavers and calves' heads, a North Carolina lawsuit that established legal precedence for ghosts, and the last surviving sample of "ectoplasm" in a Cambridge University archive.