BOOK REVIEW : Existential Allegory on Racism, the Past : TURNING BACK THE SUN, <i> by Colin Thubron,</i> HarperCollins, $20; 208 pages

This novel appears to be an allegory, set in a place that could be the Australian Outback (except that in the novel, their summer comes in our summer; their winter comes in our winter), or it could be, for instance, Arizona in the 1880s, or even Victorville, Calif., at the beginning of this century.

The twin themes here are racism and the influence that our past carries with it into our present.

Dr. Rayner has grown up in a provincial beachside capital where he has led a sheltered, privileged childhood. Again, this could be Brisbane, Bombay, West L.A. Rayner was close to the sea and lived in a temperate “civilization.”

Then a burst of bad luck changes his life. His mother dies in a car crash; he is left with a bad limp and, since he has not been able to study adequately for his exams, he’s sent by the government to a remote desert outpost a thousand kilometers inland and south.

Rayner hates it and goes on hating it for the next 15 years. He longs for his old life in the Capital, as well as the childhood “gang” he has left behind.

The only one of his old friends who dwells in this town is Ivar, a power freak from way back who works in the military. The town, like Victorville, has mines and factories and plants nearby and is linked to the Capital by a railroad.

The whole purpose of the town is utilitarian: Material possessions and entertainment are--at least in Rayner’s eyes--the only things that matter here.

The white population--immigrants from every country in the world--coexist uneasily with the indigenous population, half-starving aborigines who lounge on public doorsteps or hang out in the malls or camp by the riverside at night, declaiming poetry, reciting epics. Everything seems harmonious enough until two whites, hacked by axes in the native style, are found, floating and bloated, in that same river.

By a trick of blood circulation, or its lack, they appear now to be half-black, half-white. It makes the white townspeople exceedingly anxious, to put it mildly.

If that weren’t bad enough, white townspeople begin to come in to the doctor’s office with a mysterious rash that starts out on their torsos and traces mysterious patterns, but the really scary thing about this rash is that it’s chocolate brown, almost as dark as aboriginal skin. The whites are sure the natives are poisoning them in the creepiest possible way; conspiring to turn them all black.

Against this background, Rayner falls in love with a fiercely independent nightclub dancer who doesn’t even want to go back to the Capital. Ivar, who has been a closet Nazi all this time, begins torturing blacks, sending out military patrols and generally behaving like a world-class thug.

Not very surprisingly, Rayner gets a chance to go back to the Capital, where everything is beautiful but very dull, and his idealized childhood sweetheart turns out to be a simpering ninny. But he can have it all back.

A handsome mansion willed to him by a maiden aunt, a beautiful wife, a lucrative medical practice.

And wouldn’t it be amazing if Rayner said, “Great stuff! I love it here in the Capital! So what if my childhood sweetheart is as dumb as a veal chop? I’m staying here, where it’s safe and I don’t have to worry about questions of racism or dread diseases or forging a meaningful relationship with that independent dancer whom I really love. Bring on the vapid meaningless parties and the languid afternoons. I’m ready !”

Well, maybe that happens. I don’t want to spoil the plot for you. I can say that “Turning Back the Sun” has something in common with that old Japanese movie, “The Woman in the Dunes,” and the Jean-Paul Sartre classic flick, “The Beautiful and the Damned,” and Albert Camus’ “La Peste.” That should give you a hint about how this existential allegory turns out.