It’s every writer’s dream to land a million-dollar book deal from a big-name publishing house, and it’s one debut author Cynthia D’Aprix Sweeney is living. Editors at essentially every major magazine as well as The New York Times are raving about her book “The Nest,” which comes out today.

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A family drama about three adult siblings confronting their screwup brother about squandering their collective trust fund, the heart of the book is more about emotional costs, not financial ones. We talked with Sweeney to learn more about the book and becoming a first-time fiction writer in her 40s.

What inspired the book and its characters?
I knew I wanted to write about adult siblings who were not really connected. So then it was a matter of [figuring out] why they were at odds with one another. I started thinking about why they were estranged from one another and why [each person] needed the money.

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Did you know how everything was going to unfold from the start?
No, I knew very little. I started writing the story while I was in graduate school [at Columbia] and Bret Anthony Johnston [author of “Remember Me Like This”] was my adviser. The first question I asked him was, “How much do I need to know about the end?” And he said, “You don’t need to know anything, but it will help if you have a sense of where you want each character to leave off emotionally.” So that was my little lighthouse in the distance.

Novels about family drama can be breezy, but “The Nest” is more emotional and complex.
I learned that if I didn’t genuinely care about what happened to [each character] then that character wasn’t working yet. I had to go back and find their vulnerabilities. ... For me, it was necessary to make the characters not just feel like a type of person I wanted to create to make a point about something but be people who are complicated.

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Your background is as a journalist. Was it hard for you to start writing fiction?
It was hard for me to get to the point where I felt I was doing it well. My first efforts were pretty terrible. It was one reason why I decided to get my [master of fine arts degree]. I felt if I had the structure of a fiction-writing program with deadlines and support, and people giving me regular feedback on my work, that I would figure out what I was doing wrong more quickly, which is true.

What is your own family like?
Nothing like the people in the book! There are four of us [kids]. I’m the oldest. We’re all pretty close, although we try to stay out of each other’s way. We’re scattered geographically, so we get together a few times a year and there is always one really heated argument, sometimes more. But we’re also really quick to forgive each other. I’m always a little distrustful of people who have zero family drama. ​

If you go:

New York City

Tonight, 7:30 p.m.
Greenlight Bookstore
686 Fulton St., Brooklyn

Wednesday, 7 p.m.
Harvard Book Store
1256 Massachusetts Ave., Cambridge

Follow Emily on Twitter: @EmLaurence