This second book of the Dīgha Nikāya, the Collection of the Long Treatises of the Buddha, collects 17 suttas that, in this case, do not correspond to The Word of Buddha himself, but are later compositions that were eventually included as a canonical collection.
The most important treatise in this book is the Mahasatipatthana, the Great Treatise on the Foundations of Practice. The suttas DN 18, DN 19, DN 20, DN 21, DN 23 are false suttas. They are marked with a double asterisk (**). The recurring themes in the false suttas with the justification of misogyny, for example, the statement that one must renounce womanhood in order to be reborn as a man: 
Another recurring theme is the mythomania in which one tries to fit the Buddha in by portraying him as a prince in a republic. Or that he had the 32 signs of the great man that would make him a circus freak. And it does not lack a list of good and bad things, similar to a list of commandments, ending with some kind of protection spell.
Like the previous ones, and because of their length, these are not speeches of the Buddha. In this case, they are long suttas intended to support the missionary work of the bhikkhus to an audience foreign to the teachings.
In addition to these two suttas, DN 24: On Pāṭikaputta stands out, an amusing tale of contempt for a fool. DN 28: Inspiring Confidence, is an enumeration of how well the Buddha explains the teachings and their superiority over others. The Mahasatipatthana and the last two suttas alone make this book worthwhile.