When Updike laughs, his thick, thatchy eyebrows mobilize. His stammer, to which he dedicated much of a chapter of his memoirs, is barely discernible, more likely to be aggravated by confrontations more stressful than this one -- those with law-enforcement officers, say, or old-line New Englanders or "people of evident refinement or distinction." In conversation, he manages the neat trick of appearing simultaneously distant and eager to please and laces his sentences with twinkly words -- kind, nice, sweet, dear, fond, happy -- that seem far removed from the ongoing mischief and eroticism of this new book.

So, why Brazil?

"Well, you know, why not."

As an 11-year-old growing up near Reading, Pa., Updike had watched the outlandishly garbed Carmen Miranda gyrate across the screen at the local movie house. By his 20s, he was reading Joachim Machado de Asis, Brazil's great 19th Century writer of irony and disenchantment. "I remember, also, in the early '60s, when Brasilia was going up, photographs in Life of this exotic architecture being placed on an empty plain. Obviously, any country's interesting" -- a vision of old French West Africa had inspired The Coup's imaginary land of Kush -- "but Brazil, somehow, especially for me."

From a week's visit in early 1992, Updike brought home enough impressions for some poems (Rio de Janiero, Sao Paulo and Brazil ) and a yearning "to see if I could write a shortish, fanciful novel, which you now hold in your hand, although it is not as short as I envisioned. This book has quite a lot of love packed into it. I thought I could write it quicker, that it would somehow write itself, but once you get going, there's more to say than you thought, and when you're writing about a strange terrain, you have to keep researching even the most elementary things, . . . and sometimes you don't find out and have to make it up. So it's harder."

The book -- a loose, modernized reworking of the romance of Tristan and Isolde -- welds together the lives of Tristo and Isabel, racial and economic opposites who fall in love under the scalding December sun of Copacabana and then travel more or less together across geography and time. Though their passion for each other is imperishable, their lives are complicated by politics, prejudice and a meddling crowd of ragged whores, assassins in silver-gray suits, time-warped bandits, thieving gold miners and a neglected shaman whose spells turn the white Isabel black and the black Tristo white.

For Updike, a psoriatic, "racially sheltered Northeast American" whose older daughter and older son are married to native Africans, there is powerful magic "in the whole idea of how your skin is in some way your fate. If I may say, psoriasis kind of forced me into becoming a writer, or at least into thinking, 'What can I do where nobody has to look at me.' So it's probably made me more skin-aware than your average citizen, and in some ways it was a modest rapture for me to write that section where Isabel's skin is dyed."

Updike characterizes the work as "a little panorama . . . the idea being that in Brazil, as in the United States in its heyday, one went west to get away and to strike it rich, if you could. And that's what my young couple do. It was fun to write a story where a lot of things happen, since I've been accused of having nothing happen in my books. And in some ways I treated Brazil as another kind of United States. It's about the same size and has some of the same peculiarities, . . . the same racial mix, the same coastal cities and then the immense hinterland. Our hinterland is no longer quite as hinter as Brazil's, but maybe Brazil's isn't as hinter as I made it seem, either."