This book begins with a discussion on the meanings of the word ‘atthakatha’, followed by an examination of the Buddhist texts, purportedly transmitted from India to Sri Lanka in the 3rd Century B.C. Certain important source-materials, based on which the present Pali Commentaries were edited and translated, are discussed together with some controversies surrounding them. The Theravada school of Buddhist thought, deriving the material mainly from the Pali Commentaries, is examined next. This is followed by a critical discussion on the editorial methods of Buddhaghosa and Dhammapala, the two prominent and important commentators in the history of Theravada Buddhism.