What's one of your earliest influential occult books?

Recently I was looking through my magical library and I came across two books by Ted Andrews, books I've had since I was 16 or 17. They were books I'd hidden away when I was 18 and told I had to burn my books or leave, because they were books that were essential to my practice at that time. I was using the exercises in them for my daily work and also to connect with the elemental spirits. And to this day those books are essential to my magical practice in terms of the information and experiences they first provided. While my magical practice has gone far afield, the principles I learned in this books still inform and guide my magical practice. The books are How to Meet and Work with Spirit Guides and Enchantment of the Faerie Realm. Perhaps what I liked best about the books then and even now is the balance between practical techniques and theoretical information. As I looked through both books the other night, I felt a smile appear on my face, rediscovering a sense of wonder I first felt when I began practicing magic. As a teenager these books were doorways to a better life than the one I was living in. They provided me a sense of empowerment, a feeling of control, and a sense that I could actively make a difference in my life by employing magic. I still feel that way, but holding those books and flipping through them brought a sense of nostalgia and happiness over the memories themselves.

And flipping through them also provided inspiration for a working I did recently and am still engaged in currently, which I'll write about on Wednesday. It illustrated to me that going back through something you've kept for almost 20 years can still provided you surprises and realizations that you can work with.

What was your earliest influential texts that changed your approach to magic?