The Seven Books of Abhidhamma
The Suttanta PiĨaka also contains discourses dealings with analytical discussions and conditional relationship of the five aggregates. Where the need arises subjects such as the five aggregates, æyatanas, etc. are mentioned in the sutta discourses. But they are explained only briefly by what is known as the Sutta Method of Analysis (Suttanta bhæjanøya), giving bare definitions with limited descriptions. For example, khandhas, the five aggregates, are enumerated as the corporeal aggregate, the aggregate of sensation, the aggregate of perception; the aggregate of mental formations (volitional activities) and the aggregate of consciousness. They may be dealt with a little more comprehensively; for instance, the corporeal aggregate may be further defined as corporeality of the past, the present or the future; the corporeality which is internal or external, coarse or fine, inferior or superior, far or near. The Sutta Method of Analysis does not usually go further than this definition.

But the Abhidhamma approach is more thorough, more penetrating, breaking down each corporeal or mental component into the ultimate, the most infinitesimal unit. For example, Rþpakkhandha, corporeal aggregate, has been analysed into twenty-eight constituents; Vedanækkhandha, the aggregate of sensation, into five; Saņņækkhandha, the aggregate of perception, into six; Sankhærakkhandha, the aggregate of mental formations, into fifty; and Viņņænakkhandha, the aggregate of consciousness, into eighty-nine. Then each constituent part is minutely described with its properties and qualities and its place in the well arranged system of classification is defined.

A complete description of things requires also a statement of how each component part stands in relation to other component parts. This entails therefore a synthetical approach as well, to study the inter-relationship between constituent parts and how they are related to other internal or external factors.

Thus the Abhidhamma approach covers a wide field of study, consisting of analytical and synthetical methods of investigation, describing and defining minutely the constituent parts of aggregates, classifying them under well ordered heads and well arranged systems and finally setting out conditions in which they are related to each other. Such a large scope of intellectual endeavour needs to be encompassed in a voluminous and classified compilation. Hence the Abhidhamma PiĨaka is made up of seven massive treatises, namely, (i) Dhammasaģgažø, containing detailed enumeration of all phenomena with an analysis of consciousness (citta) and its concomitant mental factors (cetasikas); (ii) Vibhaģga, consists of eighteen separate sections on analysis of phenomena quite distinct from that of Dhammasaģgažø; (iii) Dhætukathæ, a small treatise written in the form of a catechism, discussing all phenomena of existence with reference to three categories, khandha, æyatana and dhætu; (iv) Puggalapaņņatti, a small treatise giving a description of various types of individuals according to the stage of their achievement along the Path; (v) Kathævatthu, a compilation by the Venerable Moggaliputta, the presiding thera of the third Great Synod in which he discusses and refutes doctrines of other schools in order to uproot all points of controversy on the Buddha dhamma; (vi) Yamaka, regarded as a treatise on applied logic in which analytical procedure is arranged in pairs; (vii) PaĨĨhæna a gigantic treatise which together with Dhammasaģgažø, the first book, constitutes the quintessence of the Abhidhamma PiĨaka. It is a minutely detailed study of the doctrine of conditionality, based on twenty-four paccayas, conditions or relations.