The neighborhood is still, unnaturally quiet in the midday glare. Children's toys lie scattered across steamy lawns, skateboards and bicycles abandoned beside front porches. Even the leaves on the mock orange shrubs are wilting. It feels as if a sudden disaster, not just a summer heat wave, had struck this Boston suburb, forcing all but the rashest of citizens to seek shelter indoors.

In a plum-color Victorian house halfway up the block, novelist Alice Hoffman, 36, rinses the lunch dishes as she steps gingerly around the family dog, Houdini. In shorts and a scooped cotton top, she looks like any suburban housewife. Upstairs her husband, Tom Martin, 35, and the couple's infant son sleep through the sweltering early afternoon. To a fiction writer like Hoffman, such a tranquil setting is fraught with danger; it could easily be shattered by forces beyond her control.

Such is the premise of At Risk, Hoffman's much talked about new novel. In the book, tragedy in the form of AIDS descends upon a typical American family living in a golden New England town. The sweetheart of the family, an 11-year-old budding gymnast named Amanda, tests positive for the deadly disease. Amanda, who has long blond hair and braces and carries a pink gym bag, contracted AIDS through a blood transfusion. "The novel is about a family and a community, what happens when tragedy tears people apart from each other," Hoffman says softly. "It's also about how they find their way back to each other."

Hoffman chose not to write a fictional account of AIDS in the gay community. "I didn't think that was my novel to write," she says. "I felt I had to write about what I knew best, which is really domestic life."

The mother of two small sons, Jake, 5, and Zachary, 5 months, Hoffman wrote At Risk to exorcise her terrors about AIDS. A writer with an admittedly phobic nature, Hoffman says her own fears were a powerful motivating force as she developed the novel. "I thought about how it would affect me if one of my children had AIDS," says Alice. "It is a book that deals with parental fears, and I certainly have a lot of them."

Hoffman decided not to interview any AIDS experts for her novel. "I didn't want to become overly concerned with the medical aspects," she says. "I didn't want to get caught up in the particulars of something. I wanted to deal with the emotional parts. This is a very personal story about one family, one community and one little girl." For accuracy, Hoffman asked Perri Klass, a writer and pediatric resident at Boston's Children's Hospital, to check the manuscript.

With At Risk, Hoffman's seventh novel in the past 11 years, the author has her first big seller. A Book-of-the-Month Club selection, the novel has been sold to Twentieth Century Fox for more than $100,000. Hoffman is donating a sizable portion of her $150,000 book advance to AmFAR, the American Foundation for AIDS Research.

Kurt Vonnegut, Toni Morrison and Joseph Heller are all Hoffman fans. But Alice's biggest supporter is Tom. "I have read At Risk more than 10 times," says Martin. "I still get choked up when I read it. I think it gets across the fears that people have without making them into villains, which is a hard thing to do."

In July, Hoffman left home for just four days to promote her book in New York and Washington, D.C. Not only does she dislike the promotional grind, she is also agoraphobic. "My grandmother was phobic," says Hoffman. "It tends to run in families, whatever the reason, and it kind of comes in cycles. I have had periods when I could go to Europe by myself and periods when I couldn't drive at all alone. I think writers and phobics have something in common. Phobics think, 'What if I get in the car and have an accident?' Fiction writers think the same way; they see the dark possibilities." Adds Hoffman, with a thin little laugh: "My phobia has been great for my writing."

Hoffman, who grew up in Franklin Square, N.Y., has been writing since she was a child. Her father, who worked in real estate, and her mother, a social worker, divorced when she was 8 years old. Alice hated high school and didn't take her own fiction writing seriously until she enrolled in an evening course at Adelphi University. After graduating in 1973, she won a fellowship to a one-year writing program at Stanford University. Gradually, her short stories began to turn up in fiction magazines, and her first novel, a story about a girl and a street gang called Property Of, was published in 1977. That same year Hoffman moved back East and met Martin. A former welder and counselor for emotionally disturbed children, he is now an aspiring screenwriter.

Refreshed from his nap, Tom wanders into the kitchen with Zack in his arms. Alice, with Houdini at her heels, warms a bottle of water for her son. For a while the only sound in the kitchen is the glug-glug of the baby drinking.

The house feels peaceful, dreamlike. But what if fiction became reality and one of her children really did get AIDS? Hoffman's face turns shadowy. "You can't protect your children from everything," she says slowly. "I hope that I would act with courage and dignity."