Guhyasamaja
The Guhyasamaja Tantra is one of the most important scriptures of esoteric Buddhism. In its fullest form, it consists of seventeen chapters, though a separate "explanatory tantra" known as the Appendix Tantra (uttaratantra) is sometimes considered to be its eighteenth chapter. Many scholars believe that the original core of the work consisted of the first twelve chapters, with chapters thirteen to seventeen being added later as explanatory material. In India, it was classified as a Yoga or Mahāyoga Tantra. In Tibet it is considered an Unexcelled Yoga Tantra . It develops traditions found in earlier scriptures such as the Sarva-tathāgata-tattva-saṃgraha but is focused to a greater extent on the antinomian aspects characteristic of the later Buddhist Tantras. It survives in Sanskrit manuscripts and in Tibetan and Chinese translation.