How and Why Buddhism declined in India, the land of its birth, is such a perplexing problem that no two opinions agree. The sectarian scholars all along have been trotting out the so-called degeneration in the moral and spiritual life of the Buddhist monks and nuns as the main reason for it. The author in the study sets forth in a new perspective reasons for the disappearance of Buddhism from the land of its birth. He has marshalled considerable literary and historical evidence to show that Buddhism declined in India as a result of a concerted and calculated crusade against it by the reactionary Brahmins who worked overtime to regain their caste supremacy, which had been challenged by the Buddha.