Tantra Kriya Yoga, the dance of lightning, is a major new contribution to the study of Yoga and Tantra. In this scholarly work, intended for those with a good prior knowledge of Yoga and anatomy, Saul Martinez, an internationally known expert on these subjects, shares his vast knowledge, explaining in detail each of the eight steps of Astanga Yoga described by Patanajali and those of the Tantra Kaula. He guides the reader through a series of practical exercises, encouraging them to try these disciplines for themselves although, as he explains, some aspects of the Tantra Kaula are secret and transmitted orally, from master to initiated disciple. Intended as a rigorous study for the use of committed teachers and students, this text is based on the practical experiences of the author and covers a wide variety of themes: anatomical and physiotherapeutic concepts applied to Hatha Yoga; Pranayama, the Vayus and Nadis; Prathyadhara and Nidra Yoga; Dharana or contemplative concentration; the Chakras; Dhyana, meditation and Samadhi. It goes on to explain the nature and practice of the Tantric Sadhana. This includes the Tantric Kriyas of Kundalini; Mantras; Yantras; Mudras and Bandhas, as well as a description of Kurlanava Tantra; the sacred sexual rite of Maithuna and the Chakra Puja. In transforming our inner energy by these methods, we may achieve the state of "emptiness" which all initiated practitioners of Yoga and Tantra seek. This important work is essential reading for scholars of Tantra Yoga and Vedanta, present and future teachers and monitors of Yoga and practitioners hoping to obtain the maximum physical, psychological and spiritual benefit from their practice.