From the book's Introduction: Phantasmal Memories - the Book of Spirits is a brand new sourcebook that expands the nature of incorporeal undead within the d20 system. Drawing up myth, legend, and popular fiction, it introduces three new templates - complete with example monsters drawn from folklore, and non-player characters inspired by the phantasms of gothic fiction - and a brand new category of spectral effect, the phantom memory. Using this book, you will be able to add whole new levels of gothic dread to your campaign world, and take your player's ghost-hunting adventurers to new heights of fear.