ESP, Hauntings & Poltergeists: A Parapsychologist's Handbook
By Loyd Auerbach

The original book (1986) called the “Sacred Text” on Ghosts by Newsweek is now available as a PDF e-book from Loyd Auerbach.  The book has a few bits of updating, but is essentially in its original “classic” form. 

The e-book is available on CD-Rom with a number of extras,
including forms to use in an investigation.