If I had to name one book it should be the book that had the greatest impact on my life.
That book is 14 Lessons in Yogi Philosophy and Oriental Occultism by Yogi Ramacharaka
That book is 14 Lessons in Yogi Philosophy and Oriental Occultism by Yogi Ramacharaka

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Can't get enough of this 8-circuit model, it makes too much sense.