Although officially abolished, the caste system has not ceased to exert a strong influence on Indian social life. It is not a problem of colour, race nor even of class. It is far subtler and harder to pin down, as Louis Malle discovers as soon as he starts to ask those awkward questions about caste that Indians are reluctant to answer. For the Hindu, division into castes is like a law of nature, a logical expression of his vision of the Universe. Castes are religious boundaries that run through heads and through hearts but not along the ground; they are those invisible frontiers of the mind that to India are so natural and to the West so incomprehensible.

How can you capture in the lens of a film camera the essence of a country so diverse, so variegated, and so paradoxical as India?

Louis Malle finds a devotion to a spiritual life that transcends the poverty of the material one and discovers that in a country as crowded as India, religion is the one way for the individual to be alone.

Southern India pretends to know nothing about the North. Its language is different, its very nature too. In Madras Louis Malle discovers a striking example of that world of opposites to be found in traditional India: thousands cramming the streets at a strange ceremony centuries old, and a family planning clinic; a film studio making folk-lore musicals, and the famous Kalachetra dance school where dancing is itself a language, a prayer, an invocation to God.

Drifting at random through the numberless villages of the South, Louis Malle finds himself in a timeless, fantastic, and to a western eye, almost surrealist world. Kerala is like a dream, with its exotic lagoons, game reserves and palm-fringed beaches - a species of tropical Paradise Lost. At the same time it's a battleground for the conflicting forces of Capitalism and Maoism, a land where even the Communists are split into three separate parties, and democracy and collectivism wrestle with the traditions of a country that by nature rejects them both.

Bombay. It's the last lap of Louis Malle 's journey through India and already it smacks of the West. Bombay is a city on the move, in the middle of an economic boom. Parsee industrialists, Muslim craftsmen, and immigrant labourers from the South all meet here in this cosmopolitan city, whose slums are as poverty-stricken as those of Calcutta, but whose modern factories, oil refineries, and traffic problems all show the shadow of the West. It's where Hinduism meets Industrialisation, where East goes West, where the India of yesterday and today meets the India of tomorrow. But what kind of tomorrow?

Turning aside from the traditional India of the Hindus, Louis Malle pans his camera on to the India of forgotten tribes and tiny sects. He discovers two versions of Utopia: one, the Ashram at Pondicherry whose disciples claim through yoga to have discovered the secret of the ultimate meaning of life; the other, the natural gentle life of the Todas, a people who live in total sexual freedom, without laws, leaders or class system, at peace with themselves and with their neighbours, and whose only problem is that they are doomed by the advance of civilisation.