This scripture describes the first Buddhist council. It was held shortly after the Buddha's death, and collected the set of rules (Vinaya) and five sets of Dhamma. Tradition holds that little was added to the Canon after this. Scholars are more skeptical, but differ in their degrees of skepticism. Richard Gombrich thinks most of the first four nikayas (see below) go back to the Buddha, in content but not in form. The late Professor Hirakawa Akira says that the First Council collected only short prose passages or verses expressing important doctrines, and that these were expanded into full length suttas over the next century.
There are five nikayas (collections) of suttas:
This includes The Greater Discourse on the Foundations of Mindfulness, The Fruits of the Contemplative Life, and The Buddha's Last Days. There are 34 long suttas in this nikaya.
This includes Shorter Exposition of Kamma, Mindfulness of Breathing, and Mindfulness of the Body. There are 152 medium-length suttas in this nikaya.