Tsong Khapa's Great Treatise on the Stages of Mantra (Sngags rim chen mo)--considered by the present Dalai Lama to be one of Tsong Khapa's two most im -portant books (along with his Lam rim chen mo)--is his masterful synthesis of the prin -ciples and practices of all four classes of Tantra, which formed the basis of his innovation in creat -ing the esoteric "Tantric College" institution and cur -ricu -lum in the early fifteenth century...