Luminous Essence is a complete introduction to the world of tantric thought and practice. Composed by the renowned Tibetan master Jamgoen Mipham (1846-1912), the text provides an overview of the theory and experiential assimilation of a seminal tantric scripture, the Tantra of the Secret Essence (Guhyagarbha Tantra). Embodying the essence of tantric practice, this text has been a central scripture in Tibetan Buddhism for well over a thousand years. Mipham's explanation of this text, here translated for the first time, is one of the most celebrated commentaries on the Tantra of the Secret Essence, which today occupies an important place in the tantric curriculum of Tibetan monastic colleges. Luminous Essence is a specialized guide meant for initiated tantric practitioners. To fully appreciate and assimilate its message, it should be studied under the guidance of a qualified teacher by those who have received the appropriate empowerments, reading transmissions, and oral instructions.