Women Thrown to Earth : FALLING ANGELS <i> by Barbara Gowdy (Soho Press: $18.95; 208 pp.; 0-939149-35-4) </i>

When Mary Field hurls herself from the roof of her house in 1969, she doesn’t abandon much of a life. Mary hasn’t been the same since she was acquitted of hurling her firstborn infant son into Niagara Falls in 1948. Since then, alcoholism has prevented her from doing much except watching TV in her bathrobe and curlers--she even devours the test patterns. Once a year, on Christmas, she leaves the house.

Mary’s three daughters are thus left to rear themselves, with occasional interference from their violent father, a traveling salesman, when losing a mistress sours his mood. “Leave It to Beaver” this suburban Toronto family is decidedly not. But then, unlike TV shows, novels always have loved unhappy families.

“Falling Angels,” Canadian writer Barbara Gowdy’s richly imagined second novel (her first was a historical romance), concerns the daughters’ different responses to life in a house “like a dangerous country.” Norma, Lou and Sandy--10, 9 and 8 respectively in the early scenes, completing high school at the time of their mother’s suicide--are the falling angels of the title, clinging to innocence and trust despite their less-than-heavenly childhoods.

Silent Norma gains weight (her jeering classmates call her “Enorma”) and turns to God, then to lesbianism. Lou, the most rebellious, poses as a delinquent but studies hard on the sly, because “no one expects her to be smart.” Sandy, the baby, develops a taste for older, married men until identical twins who are “into swinging”--this is 1967, after all--scare her into the arms of a boy on the football team, and an unplanned pregnancy.

Handled badly, such material risks cliche. We’ve seen enough ‘50s melodramas about bad girls from broken homes becoming prematurely fallen women in cheap motels. What rescues Gowdy from this trap--the Field girls too, for that matter--is humor. Lou is fond of declarations such as “Considering our upbringing, it’s amazing one of us is normal.” Even brooding Norma is bestowed with wry insights: She “thought of her breasts as intelligent life with insane, disgusting ambitions.”

The novel’s strongest section is a comic nightmare called “Disneyland--1961,” which appeared in last year’s “Best American Short Stories.” Instead of the promised vacation to Disneyland, Jim Field takes his family for a two-week trial run in their newly constructed bomb shelter. He brings his trusty guide (“Pioneers of Self-Defense”), some Life magazines, canned food and three cases of whiskey--which the girls need as desperately as do their parents, especially after the water supply runs out. But Jim is determined to stay the full two weeks: “As adults, the girls agreed that if one of them had a burst appendix, he would have tried to treat her himself with his hunting knife and Bactine.”

Most of the men that the Field girls encounter are as capricious and cruel as their father. Gowdy structures “Fallen Angels” as a series of the girls’ escapes from these threats. The kindly old man with a Santa Claus beard who helps the girls when they run away from home turns out to be a child molester; the married men who call Sandy “doll” and take her for rides in their shiny cars all are menacing.

Gowdy’s relative inexperience as a writer shows in her method for tying the pieces of her chronology together. The images of falling, heaven and angels threaded through the narrative often seem too heavy-handed and artificial a way to gain narrative cohesion. Written in short sections and short, simple sentences, with frequent changes of tense, the episodes often feel episodic. Especially in the sections told from the girls’ childhood points of view, Gowdy doesn’t quite achieve the guileless lyricism for which she aims.

But this novel, unlike many others, gets better as it progresses. These characters clearly grew on Gowdy as they grew up and developed habits, hobbies and fantasies. In the first chapters, a reader may barely be able to tell the Field girls apart; by novel’s end, they’re firmly and movingly differentiated, each with her own method for accommodating hardship and disappointment.