THE ART OF MEMORY and Francis A. Yates
Memory Gardens, Memory Palaces, and Memory Theatres

Who would have thought that a modest english historian would write books with such a critical impact on our understanding of the western esoteric tradition? Read "The Art of Memory" and "Giordano Bruno and the Hermetic Tradition"; these two books will transform your practice and revolutionize your understanding of how modern qabalah was constructed..

You will never look at hermeticism and the western mystery schools the same way again.

The Art Of Memory discusses the pre-renaissance and renaisance obsession, now mostly forgoten or ignored, with the recreation of the ancient greek "art of memory" which allowed greek rhetoricians and intellectuals to memorize long speeches, stories, whole books, and much more by using a visualization technique which was called "the memory garden".

Students of modern qabalah, especially the variants that are part of the western mystery tradition and western occultism, will quickly recognize that the reaissance ideas of the memory garden, memory palace, and memory theatres & memory cabinets, were combined with the judaic kabbalah to produce the system of mental exercises and world-models that make up much of modern european cabala. 

Her books are getting a bit harder to find, who knows if they will be reprineted when the current printings run out. Many are only available used. I suggest grabbing them while you can.