This book, one of the concluding portions of the Mahabharata, is notable for several reasons.
The first is a long interposed section of Upanishadic material, known the as Anugita. This occupies a large part of this book; Arjuna asks Krishna to repeat his battlefield discourse (the Bhaghavad Gita in Book 6). What follows is a somewhat disjointed metaphysical treatise which was probably composed at a much later date than the main narrative.
Following the Anugita is the story of Utanka, a disciple of Krishna who undergoes a fairy-tale-like journey involving a cannibal king, magic earrings and a journey to the underworld.
Finally there is the story of the great Horse Sacrifice of Yudhishthira, which resumes the main narrative of the Mahabharata. The Horse Sacrifice was the premiere ceremony of the Yajur-Veda, a scapegoat-like expiatory ritual of unmatched extravagance. A magnificent wild black horse is set loose from Hastinapur, the Kuru capital. In hot pursuit is the Kuru army, let by Arjuna. They must follow this horse, wherever it may lead. They are required to engage in ritual combat with the Kshatria (military caste) of whatever territory it enters, without killing the leader of the opposing force. Then they invite the trespassed nation to the sacrifice. In the course of this journey they settle some old scores.
The horse returns to the capital city, and the ritual starts; amidst a pavilion of pure gold the horse is sacrificed. However, at the last moment, a mongoose with a gold head pops out of the ground and states that the Horse Sacrifice is of less meaning than a Brahman who sacrificed a handful of barley during a famine. With this bizarre anticlimax the book--and possibly the original narrative of the Mahabharata--ends.
--John Bruno Hare, January 16, 2004.