The Digha Nikaya is the first book in the Sutta Pitaka, the first division of the Tipitaka, the sacred scriptures of Buddhism. Digha means ‘long’ and nikàya means ‘book’ or ‘collection’ and this name is used because the thirty four discourses or suttas in this book are lengthy – the longest being forty six pages in the English translation. Nearly half the discourses in the Digha Nikaya take the form of debates or dialogues between the Buddha and others. Some of these debates are very lively and give a fascinating glimpse of how the Buddha used logic, dialectic, reason and gentle persuasion to win people to his point of view. As in most of the other divisions in the Tipitaka, the discourses in the Digha Nikaya do not seem to be arranged in any particular order.
The Long Discourses of the Buddha. trans by M.Walshe, 1987.