The three divisions of the Tipitaka are the :
Vinaya Pitaka (Basket of rules on conduct)
The collection of texts concerning the rules of conduct governing the daily affairs within the Sangha (the community of bhikkhus (ordained monks) and bhikkhunis (ordained nuns)). Far more than merely a list of rules, the Vinaya Pitaka also includes the stories behind the origin of each rule, providing a detailed account of the Buddha's solution to the question of how to maintain communal harmony within a large and diverse spiritual community.
This collection of suttas, or discourses, attributed to the Buddha and a few of his closest disciples, containing all the central teachings of Buddhism.
and subsequently included teachings that formed the
Abhidhamma Pitaka (Basket of the Higher Teachings)
which sets out a collection of texts, comentaries in which the underlying doctrinal principles presented in the Sutta Pitaka are explained in a systematic theoretical framework that can be applied to an investigation into the nature of mind and matter.