A cadaver is a dead body. The book you are referring to is Stiff:The Curious Lives of Human Cadavers, by Mary Roach. She discusses decay, burial and alternatives to burial. It reviews various techniques for verifying that someone died from the past to the present time. She interjects humor into a scientifically accurate book about death. Roach talks about seeing her first cadaver which was her mother. Her mom was "never a cadaver"--this refers to the fact that the person her mother was is gone and that cadavers lack dignity. Researchers use cadavers to advance science, but a cadaver is not the person who once inhabited the "hull". Some chapters deal with human decay, body snatching, decapitation, cannibalism, composting and other interesting topics.