Four Generations Down Under : IT’S RAINING IN MANGO<i> by Thea Astley (G.P. Putnam’s Sons: $17.95; 208 pp.) </i>

Hot. Sticky. Intense. “It’s Raining in Mango” is about four generations of the Laffey family in the seductive, brutal world of Northeastern Australia. The intricate novel reads like a dream reunion where relatives swap stories with ancestors and descendants about disease, flood, racism, violence. They talk about how things never change. Like the characters in Sartre’s “Huis Clos,” the Laffeys discover there is no way out. Australia is the end of the earth. Yet they maintain an almost inexplicable will to continue on the edge of despair.

Thea Astley’s powerful 10th novel follows a white Catholic family from the 1860s to the 1980s through immigration, settlement, desertion, suicide and rebirth. Shards of family legend intersect at provocatively odd moments. It resembles an album in which photos that seem carelessly placed actually establish a revealing psychological order.

In the 1860s, Jessica Olive and Cornelius immigrate to Cooktown and their family becomes “Bedouins of the sticky leaf.” Cornelius practices a roving form of journalism, enthusiastic about frontier possibility and outraged about the violent racism of other white settlers. Hardship tears the family to shreds. Fourteen-year-old Nadine has a baby, then runs away to join a brothel. Eventually Cornelius abandons Jessica Olive and their son George and Nadine’s son Harry. Jessica Olive battles on, running the Port of Call Hotel and raising the two boys. Years later George buys property in the rain forest near Mango and has two children, Connie and Will. Both Connie and Will are transformed by World War II--Connie because of her brief marriage to an American serviceman, which produces a son, and Will because of a gay affair that haunts him until his suicide in 1983. The book opens with Connie’s son Reever trying to preserve Mango from development bulldozers, although if there’s one thing he should have learned from Laffey history it’s that you can’t preserve anything in.

Astley’s Australia is an arduous land that shapes a willful people--circumscribing their daily lives and seeping into their bones. No satisfaction goes unabated. Even in her title, she dampens the lush pleasures of Mango. “Cut off, Jessica Olive thought, peering critically about, sniffing at woodsmoke. But when were we anything but that, she mused, in this dangerously new country?

The Laffeys hold on to each other for self-definition in the natural and social wilderness. Their relationships are engaging, addictive, repulsive and tenacious--from the reckless hardiness of Cornelius’ fatherhood to the incestuous attraction between Connie and Will. The story is told in bloodlines. Anti-epic in form, “It’s Raining in Mango” is a tight 208 pages, compressing individual stories, as if squeezing out all the air or hope, as if all that mattered were where the line was leading. “ ‘I am Jessica Olive,’ he heard her say absent-mindedly over breakfast. ‘I am Cornelius and Nadine and George.’

“ ‘So am I,’ Reever says as he flings muscle about the house. ‘So am I.’ ”

Even outside the family, Astley’s portraits are drawn with compassionate intensity. She introduces aborigines, adventurers, hippies and prostitutes. Behind everyone lurks the shadow of the drifter: from Cornelius to the wild bushman who impregnates Nadine to the starving traveler who visits little Connie and Will, to Reever, projected five years into the future.

For Astley the Australian promise always falls short. If it is not Sartre’s Hell, it is Purgatory. She juxtaposes Catholic images of temptation, sacrifice and redemption. “It’s Raining in Mango” reveals the hypocrisy of the Church (through the blustering Father Madigan) and the urgency of Faith (through Reever hanging from a tree to halt the bulldozers). This complex, intimate narrative might be compared to a secret rope, made of seemingly random bits and strongly knotted, woven by a prisoner to pass the time. The rope becomes, alternately, a rosary, a noose and a lifeline.