The Diamond Sūtra, the Vajracchedikā, is a dialogue between the Buddha and Subhūti on non-attachment: the bodhisattva vows to liberate all beings, yet sees no being to liberate. A printed copy from 868 found at Dunhuang is the oldest dated printed book. It was especially important in Chan.
Diamond Sūtra
A Perfection of Wisdom sūtra on the bodhisattva who saves beings without perceiving any being saved.
Also: Diamond Sutra, Vajracchedika