In the Eighth Century of our era, the Tibetan translator Vairochana went to India and returned to Tibet with the Tantras of the Great Perfection. All are in agreement that the Five Early Translations and Thirteen Later Translations are among the earliest scriptures to be translated into Tibetan, but there is some lack of agreement about the titles and contents of these collections. In the centuries following these translations the dynasty that ruled Tibet crumbled, and after a long period of darkness the love of learning was rekindled by newly arriving teachings from India. By the Twelfth Century, more than three hundred years after the life of Vairochana, those who held to the teachings from his time became called the Ancient Ones or Nyingma, while those who held to the new teachings from India were called Modern Ones or Sarma. Many writings had survived the centuries of upheaval in the possession of private persons, being copied and passed on as appropriate, but many titles had come to have multiple versions, both brief and extensive, and many differing lists of titles for the Eighteen Tantras exist. It was in this environment that Nyima Dorje, a minor cleric from gNyi-ba, did the work of putting together an edition of the Tantras of the five early and thirteen later translations that includes two full sets of eighteen Tantras. The first is a collection of extensive versions of each title. This is then supplemented with the quartet of the Cutting through Samsara at the Root cycle, which contains within it summary versions of the eighteen Tantras. The Tantras of the Five Early Translations are in The Filthless Tantra that is Equal to the Sun and Moon. The Tantras of the Thirteen Later Translations are in The Unborn Tantra that is Equal to a Precious Jewel. Nyima Dorje’s edition of the Five Early and Thirteen later Translations was canonized into the Hundred Thousand Tantras of the Ancient Ones (Nyingma Gyubum), which is where these Tantras are found today.In the classification system that divides the Great Perfection literature into three sections: The mind section, the space section, and the upadeśa instruction section, the Eighteen Tantras belong in the mind section, and are considered to be core reading in this area. This book has 597 pages.