Researchers can uncover far more information about ghosts and haunted places by exploring the site's layers (literal and figurative) of history. Gettysburg has been called "acre for acre the most haunted battlefield" in the United States. This book unearths the veracity of that perception. The excavation will involve "digging deeper" into the multiple layers of haunting uncertainties that may exist on the battlefield and in the town. This book also outlines a new research strategy and field methodology that can be used by the serious investigator to document these multiple haunted layers of uncertainty. This approach, called "P.O.P." (Participate-Observe-Perform), is based on the author's decades of experience (both in the field and on "stage") in the disciplines of archaeology, cultural anthropology (ethnography), and performance studies (including acting in films, on television, and in theatre). A "ghost excavation" that incorporates the "P.O.P." technique is an iterative process that can be used at any haunted location, not merely one that is historically multi-layered.