The first book of the Dīgha Nikāya, the Collection of the Long Discourses of the Buddha, collects 17 suttas that do not fit into the typical format of discourses, but are groupings created centuries later managing to be classified as another canonical collection.
While the suttas of the canonical collections: Saṁyutta, Majjhima and Anguttara Nikayas, aim at explaining the word, doctrine and teaching of the Buddha as well as providing some circumstantial data, this book, on the other hand, is a heterogeneous compilation of diatribes against the different beliefs that clashed with the incipient Buddhism.
Diatribe, or "debate", is the name given to a short ethical discourse, specifically of the type composed by the Cynic and Stoic philosophers. These popular moral readings often had a polemical tone directed against individuals or social groups. In this case, they leave no community, belief, faith or religion of the time unattacked.
This book seems to be composed to be given to Buddhist missionaries to be used as a manual for debate against other religions in order to gain followers. This is the tone of most of the first thirteen discourses. Neither mythomania nor millagery, which the Indian public has always been so fond of, is disdained.
If we study their structure, we immediately see that they are completely foreign to the canonical ones and their content, in general, is composed of a libel against a religious group, followed by a series of short-paste of canonical suttas selected without much criterion.
DN 9. With Poṭṭhapāda, its unknown author goes into a series of dialectical traps until he reaches a point where he finds himself unable to get out and resolves it by complicating everything even more so that nothing is clear. In DN 13. The Three Knowledges, the Brahmins are blamed for the same vices and defects as the Buddhist monks. The rest of the false discourses do not try to imitate the regular structure of the suttas and neither the wording nor the content, which shows a short knowledge on the part of their authors of the rest of the Nikayas.
They are marked with a double asterisk (**).
Finally, it is strange that this collection is the most popular among today's Buddhist followers.
Three of the four great discourses are also collected: the Mahapadana, the Mahanidana, and the Mahaparinibbana.
But the stain of falsehood also extends through two of the great discourses: the Mahapadana, or The Great Chronicle of the Buddhas, which is a pamphlet of an exaggerated baroque excessive even for oriental taste, and the extensive Mahaparinibbana, which is not free from falsehoods spread throughout its extensive writing.
On the contrary, the Mahanidana, or Great Discourse of the Causes, is an exhaustive compilation of the theory of Dependent Origination in a single text, and the Mahasatipatthana, or Great Discourse of the Instructions of Practice, does the same with different practices. It is not all of them, but those that it deals with it does so in depth.
These two speeches alone make this book worthwhile.