Atthakatha (Pali for explanation, commentary) refers to Pali-language Theravadin Buddhist commentaries to the canonical Theravadin Tipitaka. These commentaries give the traditional interpretations of the scriptures. The major commentaries were based on earlier ones, now lost, in Old Sinhalese, which were written down at the same time as the Canon, in the last century BCE. Some material in the commentaries is found in canonical texts of other schools of Buddhism, suggesting an early common source.
As with the Canon itself, the contents of collected editions of the Theravadin commentaries, compiled from the fourth century CE onwards, vary between editions. The minimal collection, found in the Thai edition (1992) includes the following (Skilling 2002).
Twelve commentaries ascribed to Buddhaghosa: commentary on the Vinaya Pitaka; one each on the Digha Nikaya, Majjhima Nikaya, Samyutta Nikaya and Anguttara Nikaya; four on Khuddaka Nikaya books; and three on the Abhidhamma Pitaka.
Commentaries by Dhammapala on seven books of the Khuddaka Nikaya.
Four commentaries by various authors on four other books of the Khuddaka Nikaya.
In addition, the following are included in one or both of the other two editions: the Burmese Chatthasangayana edition (a list of contents can be found in Thein Han 1981) and the Sinhalese Simon Hewavitarne Bequest edition.
Buddhaghosa's Visuddhimagga, a systematic presentation of the traditional teaching; the commentaries on the first four nikayas refer to this for the material it details. In both Sinhalese (Mori et al. 1994) and Burmese
The Patimokkha (Pruitt & Norman 2001, page xxxvi) and its commentary Kankhavitarani, ascribed to Buddhaghosa
Commentary by Dhammapala on the Nettipakarana, a work sometimes included in the canon
Vinayasangaha, a selection of passages from Samantapasadika arranged topically by Sariputta in the twelfth century (Crosby 2006)
Saratthasamuccaya, commentary on the Paritta. In Sinhalese (Malalasekera 1938).