Those would be Frank and Paulette, soon to split, and their three children, Billy, Scott and Gwen. What Haigh – who starts a series of five local readings Tuesday July 8 – does is jump from character to character and from generation to generation, imbuing all of her people with both flaws and attributes. "I find myself in the position of defending characters who behave badly," Haigh says – though not so much here as in previous books. In "The Condition," she says, "There no white hat/black hat characters."

"I never do know when I start working where it’s going to go," says Haigh, who lives on the South Shore and has indeed spent time on the Cape. "Outlining has never worked for me. There’s a lot of suspense for me in writing the first draft. I never think how long it’s going to be, it comes out the length it comes out at. I just start writing and the choices are made in the process of writing. I gravitate towards what fascinates me. I like looking at the way different people remember the same event. With families, it’s always interesting. I liked all of them a great deal. I fall in love with all my characters in every book."

The book moves from ’76 to the present; characters age, develop, regress, succeed, fail, make changes in their lives, and have change thrust upon them.

"Two of the most important choices," says Haigh, "are where it begins and where it ends. All of them have a life before page one and all a life after it ends. It’s a sign a success if the reader is still curious at the end." Trust me, we are.

Haigh: "It pains me to make bad things happen again and again, but without misfortune, there’s no novel. You have to have conflict." Haigh, who says the book took three years to write (normal for her), spent time with girls and women who had Turner’s Syndrome – both back in the ‘70s and today. In the ’70s, it was an especially lonely state to be in; now, Haigh says, there are many more support groups. Turner’s women are stunted physically. They are short, look like girls, and cannot conceive. "Gwen understands pretty clearly the science behind it," says Haight, "and lives with the knowledge, but for this one chromosomal glitch, her whole life would be different. That is so fascinating to me. A classic ‘what if?’ scenario. We live in a world we’re so judged by the way we look, women more than men. Every part of her life would have been different: her childhood, educational, career, social life, dating. I don’t think she’s bitter about it. She’s almost 35 and known she has since 12 years old."

As to Frank, an MIT scientist, and Paulette, Haigh says "when you first meet them it’s an imperfect marriage, but they’re pretty skilled at ignoring it or working around it, but when Gwen is diagnosed, a chasm opens up, a crisis becomes a flash point. Everything not working is attributed to this."

Haigh gets a lot of the details right – even incidental ones like the horror of Boston driving, worse than New York even – "a very emotional driving culture," she says. She uses a New Order song to express sorrow and pain. he writes about how a carefree life in the pot culture turns ruinous.

As to her process, Haigh says, "I show up every day and make a stab at it. There are days I have a negative word count; I get rid of what I wrote the day before. I go through cycles where I’m not moving forward, I’m very regular, like a banker. I can’t fathom just waiting to feel inspired." She’s not looking for Hollywood to pick this up. "I love movies," she says, "but I never had the urge to write movies. When you’re writing novels you’re unfettered, and there’s no collaboration, and writing a screenplay can be the seventh circle of hell. And my book has very few car chases."

Haigh’s reading tour: Tuesday July 8 at Newtonville Books at 7, Wednesday July 9 at Porter Square Books at 7, Thursday July 10 at Borders Boston at 7 – and then at the of the tour – Friday Aug. 8 at Jabberwocky Bookshop in Newburyport at 7and Thursday, Aug 14 at Odyssey Bookshop in South Hadley at 7. All free.Haigh enjoys these outings. "It’s fun to do readings and talk to people, so much easier than writing," she says. "I love meeting readers and talking about books.’’

Newtonville Books, 296 Walnut St., Newtonville

Porter Square Books, 25 White Street,

CambridgeBorders, 256 Grossman Drive, Boston,

Jabberwocky, 50 Water St., Newburyport

Odyssey, 9 College St., S. Hadley