Mysteries by Colin Wilson...
This is a 633 page book that takes on the task of explaining everything from dowsing, to UFOs, to ghosts, etc. It's very well written and, for such a lengthy book, a very easy read. Colin Wilson presents a point of view that many things that are unexplained are direct creations of the human psych. While covering such a wide range of topics, he offers references for all of his research and, very often, delves into history to explain his conclusions or thoughts. Throughout the book, he often refers to the work of Tom Lethbridge. (Lethbridge was a noted English archeologist who authored many books, including titles on the occult.)
One of the more interesting chapters in the book dealt with Lethbridge's dowsing work. He discovered that everything on earth has a unique vibration and by varying the length of the dowsing pendulum, one could assign a measurement to everything (metals, animals, emotions) on a 40 inch scale. The scale repeated itself once he got beyond 40 inches, but seems to suggest a different dimension of time. He also discovered that certain items recorded emotions and this affected the way the pendulum reacted. For instance, stones thrown in anger had a different scale than untouched stones.
All in all, Mysteries is an excellent book. Colin Wilson also authored a book called "The Occult", which was a best seller. I haven't found a copy yet, but after reading Mysteries, The Occult is on my list.
For more information on Tom Lethbridge's work, check out this link...
http://www.tc-lethbridge.com/home/