The twelve lessons forming this volume were originally issued in the shape of monthly lessons, known as " The Advanced Course in Yogi Philosophy and Oriental Occultism" during a period of twelve months beginning with October, 1904, and ending September, 1905. These lessons were intended as a continuation of, or sequel to "The Fourteen Lessons in Yogi Philosophy and Oriental Occultism" issued during the previous year. We have been urged to print these " Advanced Course " lessons in book form, and the present volume is the result.