The Yantra is a set of tantrik tools that consist of power diagrams, which let you embark on the spiritual journey of return to the primordial center, and ultimately to perceive the unity of self and cosmos. Herere a few good books for Yantra enthusiasts.
This study discusses all types of Yantras found in the Vedas and explains the concept of the sacred geometrical forms and the associated mantras, rituals, and meditation techniques. In sum, its an in-depth and analytical work covering almost all aspects of Yantra from its application to temple architecture and sculpture to its traditional use in magic.
This is a kind of do-it-yourself book with a simple instructions to use the Yantra system. Written by Richard Webster, it's meant for the uninitiated who want to learn about Yantra in a jiffy, and lay their hands on the divinatory squares to create charms and talismans for prosperity, luck or just fun. Try it at home but with caution!