The Diamond Sutra and The Heart Sutra are texts belonging to the Prajnaparamita category of Mahayana Buddhism, which translates to 'Perfection of Wisdom'.
The Prajnaparamita literature consists of thirty-eight different books, composed in India between 100 B.C. and A.D. 600. The judgement of thirty generations of Buddhists in China, Japan, Tibet and Mongolia has singled out two of these as the holiest of the holy - the Diamond Sutra and the Heart Sutra, both perhaps of about the fourth century of our era. The first is known in Sanskrit as Vajracchedika Prajnaparamita, the 'Perfection of Wisdom which cuts like a thunderbolt'. The second sets out to formulate the very 'heart', 'core' or 'essence' of perfect wisdom, and is as diligently studied in the Zen monasteries of Japan as in the lamaseries of Tibet.
This English translation has rare insights into this ancient text.