This second book of the Dīgha Nikāya, the Collection of the Long Discourses of the Buddha, collects 17 suttas that, in this case, do not correspond to The Word of Buddha himself, but are later compositions that ended up being incorporated as a canonical collection.
The most important discourse in this book is the Mahasatipatthana, the Great Discourse on the Fundamentals of Practice. The suttas DN 18, DN 19, DN 20, DN 21, DN 23 are fake suttas. They are marked with a double asterisk (**). The recurring themes in the false suttas with the justification of misogyny, such as, for example, explains that one must renounce femininity to become reborn as a man: 
Another recurring theme is the mythomania in which they try to fit the Buddha by passing him off as a prince... in a republic. Or that he had the 32 marks of the big man that would make him a circus freak. And there is no lack of an enumeration of good things and bad things similar to a list of commandments, ending with a kind of protection spell.
As the previous ones, and because of their length, these are not discourses delivered by the Buddha. In this case, they are long suttas conceived to support the missionary work of the bhikkhus among an audience alien to the Teachings.
Apart from these two suttas, DN 24: About Pāṭikaputta, an amusing tale of scorn about a fool, stands out. DN 28: Inspiring Confidence, is an enumeration of how well the Buddha explains the teaching and its superiority to others. The Mahasatipatthana and the last two suttas alone make this book worthwhile.