The rightful owner of this book is no less than the old and mighty wizard and necromancer Joseph Curwen. Tales told by experienced travelers speaks of mortals coming in possession of this book, and with the guidance of it these mortals is said to have learned the basics of necromancy.
Some tales even speaks of mortals actually performing the blasphemous act.
If you, brave adventurer, want to add some knowledge of necromancy to your experience then seek out the farm of Joseph Curwen located somewhere in Aphextwin's area, and start to explore its secrets.