Dr. Nida's Path to Rainbow Body provides a wonderful initial overview of the marvelous teaching of the Yuthok Heart Essence, the principle spiritual teaching employed in Tibet for the training of physicians in continuous use in Tibetan medical schools since the 12th century, the time of Yuthok Yonten Gonpo the Younger. This book gives a brief but thorough introduction to this unique method of the doctor's essential inner training that must precede and complement the vast external learning that must be mastered over many years of medical school and early practice.