The Vishnu Purana (Sanskrit: विष्णु पुराण, Viṣṇu Purāṇa) is a religious Hindu text and one of the eighteen Mahapuranas. It is considered one of the most important Puranas and has been given the name Puranaratna (gem of Puranas). Presented as a dialogue between Parashara and his disciple Maitreya and divided into six parts, the major topics discussed include creation, stories of battles fought between asuras and devas, the Avatars (divine descents) of Vishnu and genealogy and stories of legendary kings.
In its listing of Puranas, the Matsya Purana credits the Vishnu Purana with 23,000 shlokas or verses, whereas the text we have runs to less than 7000. Such over-reckonings in old sources are hard to account for, but if there was a much longer version it is agreed that the one we have shows no signs of abridgement or structural incompleteness and is "incontestably entire".
Read more about Vishnu Purana: Contents, Date of Composition