The ‘Perfection of Insight’ (Prajñā-pāramitā) sūtras were composed over a long period, with the nucleus of the material appearing from 100 bce to 100 ce, with additions for perhaps two centuries later. There followed a period of summary and restatement in the form of short sūtras such as the Diamond and Heart Sūtras, c.300–500 ce, followed by a period of tantric influence extending from 600 to 1200 ce. The oldest text is the Aṣṭa-sāhasrikā-prajñā-pāramitā Sūtra (The Perfection of Insight in Eight Thousand Lines). The place of origin of the Prajñā-pāramitā is disputed: the traditionally accepted area is south India but there is evidence of its presence also in the north-west.
The Prajñā-pāramitā literature was innovative in two principal ways. First of all it advocates the Bodhisattva ideal as the highest form of the religious life, and secondly the ‘insight’ (prajñā) it teaches is into the emptiness (śūnyatā) and non-production of phenomena (dharmas), rather than into their substantial (albeit impermanent) mode of being as previously assumed. The scholar who pioneered research in this field, Edward Conze, summarizes as follows: ‘The thousands of lines of the Prajñā-pāramitā can be summed up in the following two sentences. 1) One should become a Bodhisattva (or Buddha-to-be), i.e. one who is content with nothing less than all-knowledge attained through the perfection of insight for the sake of all beings. 2) There is no such thing as a Bodhisattva or as all-knowledge or as a being or as the Perfection of Insight or as an attainment. To accept both these contradictory facts is to be perfect’ (The Prajñā-pāramitā Literature (1978), 7–8 Tokyo: the Reiyukai). Other interesting developments in the Perfection of Insight literature are the concept of skilful means (upāya-kauśalya) and the practice of dedicating one's religious merit (puṇya) to others so that they may gain enlightenment (bodhi).