Srimad Devi Bhagavatam was written by Rishi Veda Vyasa, and stretches over 12 books and 18000 verses. It is replete with Shakta philosophical reflections, making it as important for the Shaktas, as Shrimad Bhagavatam is to the Vaishnavas.
Though modern scholars classify it as an upapurana (a sub Purana), its author Veda Vyasa classified it as a ‘Maha Purana’, notions of which can be found at the end of chapter eighteen:
"Thus ends the eighth chapter of the first Skandha in the Mahapurana Srimad Devi Bhagavatam of 18,000 verses by Maharsi Veda Vyasa".
The Devi-Bhagavata Purana extols the virtues of the goddess Durga as the supreme being. It has become (along with the Devi Mahatmya of the Mārkandeya Purana) a basic text for Devi worshipers, Shaktas.
The final chapters (31-40) of the Srimad Devi Bhagavatam are known as, The Devi Gita (Song of the Goddess).