Theodore Sturgeon was one of the most important science fiction writers of the mid-twentieth century. He is also known for what has come to be called "Sturgeon's Law." Tired of defending science fiction as a literary art form, when asked if he didn't agree that 90% of science fiction was "crap," he allegedly responded, "90% of everything is crap."
I have a personal library of several thousand occult books that I've collected over the years. Many are quite old, but some were published barely a decade or two ago. Most people, unless they are collectors, won't recognize their names and certainly won't have read them. Why have they been forgotten? Sturgeon's Law. They fall into that 90% category.
That, however, is really good news. It means that the older books that are known are often part of that 10% of superb value and information. Combine them with clarifying notes and commentary from modern experts, and their value increases many times over. These are the true sourcebooks of magick. Virtually all forms of magick today can be traced back to these classic books. Unfortunately, some of the modern books falling into the 90% category may actually make things more difficult and complex. That's why studying and working with the original books is invaluable for any student and a must for any practicing magician who wants to return to the source for higher levels of magickal knowledge and power.
One example of this is Henry Agrippa's Three Books of Occult Philosophy. It was originally published in 1531. In 1801 much of it was copied by Barrett to make The Magus. That book inspired people such as Eliphas Levi, starting what has been called the "French Occult Revival" that resulted in groups such as the Golden Dawn and occultists including Mathers, Crowley, Regardie, and others. If you want to know the source of magick, you must get this book. It's that simple. For years, there were no versions available. I was lucky enough to obtain a three-volume hardcover set from England over twenty years ago. Today that set, without any commentary or notes, would cost you many hundreds of dollars. That's good for collectors, but not for practitioners. Now, for a fraction of that amount, you can get the entire set in one volume with expert notes and commentary by famed occultist Donald Tyson.
The book includes information about astrology, medicine, history, herbs, geography, animals, angels, devils, Witches, charms, the weather, and a host of other subjects. You'll find accurate drawings of magickal seals, sigils, and magic squares, and you'll explore the practical Kabbalah, geomancy, the elements, the humors, and the Soul of the World. This is the most complete repository of Pagan and Neoplatonic magick ever compiled. Tyson's detailed annotations clarify difficult references and expand upon them, making Agrippa's work more accessible to the modern reader.
For centuries, The Key of Solomon has been one of the most important books on the practice of magick. There have been many books that discussed it and a few reproductions of the same original text with little added to it. Now, Stephen Skinner and David Rankine have written something incredible. The Veritable Key of Solomon has three entirely new, never-before published versions of the key, including the most detailed version ever. It includes their expert commentary on all three of the manuscripts as well as information on the original Greek manuscript on which parts of the Key are based. This is the "real deal" on how to summon spirits and have them do your bidding.
Although nowhere near as old as these two books, I also have to include one of my favorite books as part of the 10% of great classic books on magick. Sometimes this book is overlooked, but I think it should be part of any magician's library. It's Israel Regardie's The Middle Pillar.
One of the things that has been left out of the earlier texts is the means to develop the skill to generate and direct magickal energy, a vital part of any magick. The Middle Pillar is the most important means for Western magicians to learn this skill. It includes all of the information and techniques along with exercises to work with energy. The editing and annotation by the Ciceros—friends and students of Regardie—makes this information clear and easy to understand so you can actually work with magickal energy. This skill will allow you to work with the systems of the two books mentioned above, as well as charge and empower any form of magick you choose to do.
Although The Middle Pillar is a newcomer compared to the other books (it's just seventy years old), I think its value is obvious and deserves to be in the same class as the other two books. That is, these three books are part of the 10% of quality books that have survived the test of time and should be in every magician's library.