Tobin's Spirit Guide by John Horace Tobin is a book that serves as a compilation of various supernatural occurrences, entities, and facts. The computer software version is hard to find and is very expensive. Egon and Ray refer to it so frequently they may have entire sections memorized. Copies of the book have been shown to be available in hardback, paperback, and electronic media. Tobin's Spirit Guide often helps the Ghostbusters with identifying entities involved in the cases that they take on.