The yantra is the Tantric tool of ritual and meditation, the power diagram that allows man to make the spiritual journey of return to the primordial centre, and ultimately to perceive the unity of self and cosmos. This comprehensive study reveals step by step the dynamics of this process, by elucidating the complex symbolic construction of the yantra with its multiple layers of metaphysical meaning. Madhu Khanna illuminates the correspondence between geometrical forms and concepts, and explores every aspect of the yantra: its associated mantras, rituals and meditation techniques; its application to temple architecture and sculpture; its traditional use in black and white magic and as a talisman.