IN HIS PREPACE to this book, Ronald Sanders describes it as a multiple ethnic history of the interrelationships among Blacks, Indians, Jews and "white Christian dominators" in the New World, which draws on a "perhaps startling variety of subject matters." The variety is such, in fact, that he sometimes seems to be merely spinning out a series of fascinating but unrelated tales. He promises, however, that the "various strands keep coming together in the end." They do not quite do that, and what emerges is therefore a sometimes puzzling design -- but one that is, all the same, unfailingly interesting and profoundly important. It extends into new areas the crucial dissections of American racial stereotypes undertaken in recent years by writers like Winthrop Jordan, David Brion Davis, George Fredrickson and Robert Berkhofer.

It is essential to try, at least, to summarize Sanders' wide-ranging story. For almost a century before 1492, he believes, the European imagination painted a favorable picture of lands beyond the horizon. In those unknown realms were mythical kingdoms, innocent "savages," lost Edens, fabled treasuries -- a rich black Christian king (Prester John) in Africa; a Jewish nation descended from Israel's ten lost tribes somewhere in Asia; and Fortunate Islands in the Atlantic, whose inhabitants lived in utopian social harmony or in a reworking of antiquity's golden age (both Renaissance conceptions).

All these legends fed the curiosity which underlay the great are exploration. They also set up an assumption that the people to be met with in the newly discovered lands would be treated, regardless of color, as human beings in familiar social roles and configurations. That was why so many early discoverers looked at red and black tribesmen, and thought they saw beneath the paint and bangles counterparts to their own princes, nobles, councilors, priests, traders, peasants and workers.

But other, countervailing forces were at work, growing stronger as the 16th century unfolded. In Spain, only recently recaptured for Christianity, the work of uprooting the tolerant, eight-century-old Moorish culture led to a zeal for doctrinal and "blood" purity that became translated into forced conversion and expulsion of Jews and Muslims, and far less sympathy for newly found dark-skinned infidels. Portuguese explorers opened the African coast, and in the expansive mood of early commercial capitalism, found nothing wrong in bartering with the Arab traders and tribal rulers of "Guinea" for cargoes of slaves. They then sold these possible kinsmen of Prester John to Dutch, French, Spanish and English planters, in a European transaction unmarked by anyone's qualms.

In all of Western Europe both Reformation and Counter-Reformation sharpened religious enthusiasm for heresyhunting at home, and for killing, dispossessing and converting heathen abroad. Even the romantic individualism of a waning chivalric order encouraged some young Hispanic gentleman-soldiers to dream of subduing faraway empires and redeeming whole peoples for God. The conquistadores were the last exemplars of the illusions that Cervantes would mock.

And so, by around 1650, it was done. The Indians became backward, impoverished wards for the Spanish friars, and perfidious Canaanites for Puritan Englishmen. The Africans became benighted subhumans -- slaves not by misfortune, as was the case in ancient times, but through natural inferiority. Some European humanists might criticize the prevailing drift, but the debate was nonetheless carried on in terms imposed by European mastery. Noble or skulking, cannibalistic or childlike, the red man and the black man were images conceived by and for Whites. The best example is the term "Indian" itself -- Columbus' error in thinking he had hit the Indies was perpetuated for all native Americans.

Such, brutally compressed, is Sanders' argument, drawn from an intensive examination of maps, atlases, plays, novellas, travel books and religious tracts, all embodying various cultural visions. I must admit to ignorance of many of them, and take it on faith that they say what Sanders asserts. Given that assumption, the book is engaging, stimulating and original.

Some of it, however, seems a bit strained. Sanders has written considerably on Jewish history, and he believes that the Jewish search for asylum was an important component in the urge to explore. He cites a long list of forcibly converted Jews (and some who were not Christianized), who played important roles in mapping and publicizing the new world, and financing expeditions. He plays with the longstanding speculation that Columbus himself was of converso descent. In my eyes, at least, he builds too many conjectures that rest on assumptions supported by possibilities.

Likewise, some of his illustrative stories, however sensitively interpreted, impede rather than expedite his argument. The tale of Estevanico, the shipwrecked black slave who became a venerated healer among the Indians, and the account of Squanto, the Indian interpreter and middleman for the settlers of Plymouth, are examples. Both mean to show that evidence of the humanity of black and red men lay under the Europeans' eyes if they cared to look. But both could have been dealt with more economically.

Senders' work sounds an optimistic note in a world where the color line is still at the center of history. What he says is that racism is not bred in the bone, but flourishes in some cultural temperatures and not in others. The implication is that it can be changed with circumstances.It is a consummation devoutly to be wished, if true, and one on which the hope of domestic and international peace for the next generation may ultimately rest.