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.