The Middle Length Discourses of the Buddha (Majjhima Nikāya)

The second of the five collections of discourses in the Sutta Piṭaka of the Pali Canon, containing 152 suttas of middle length, arranged in three parts. In the Theravāda tradition these are teachings of the Buddha and his leading disciples; a parallel collection survives in Chinese as the Madhyama Āgama. The collection covers almost the whole of early Buddhist teaching. It includes the Buddha's own account of his search and awakening (MN 26 and MN 36), the Satipaṭṭhāna Sutta on the foundations of mindfulness (MN 10), the simile of the raft that is left behind once the river is crossed (MN 22), the poisoned arrow, told to a monk who demands answers about the universe before he will practise (MN 63), and the dialogue with Vacchagotta about where a fire goes when it goes out (MN 72). Many discourses are debates with Jains, brahmins and wanderers, which makes this collection especially useful for philosophy.

It is the best single collection for seeing early Buddhist arguments about self, suffering, causation and practice as dialogues, rather than as lists of doctrines.