Many books have been written about Halloween. The first of these books was called The Book of Halloween by Ruth Edna Kelley.
Kelley, a librarian, originally published this book in 1919. In it, she first tries to give an account of the origin of Halloween and then a catalog of Halloween practices from the various countries that observe it. I believe her account of the origin of Halloween is somewhat flawed, which is not surprising considering she didn’t have a lot of reference material to work with. What is more surprising and what was for me the big take away of the book was the catalog of practices. You don’t find much about trick or treating here, nor about monsters and costumes and all the things we associate with Halloween today. Instead, you find a bunch of ancient country customs that were mostly designed to tell the future rather than provoke terror. There were things like looking into mirrors and running around a house and pulling cabbages and a bunch of other things I had never heard before. Most of these practices and most of this concept of Halloween have vanished today, but it was interesting reading about them. It also added to my understanding of the holiday.
The Book of Halloween is in the public domain, so you can get it real cheap from Amazon.com. You might even find some free copies there (I did), and you can find the entire book on several websites as well. I can guarantee that it won’t be what you are expecting, but I can still suggest it as a good source of insight into the day.