When Lynn Steger Strong’s “Float Test” opens, Jude, the narrator, is gathering with her three siblings and their father in Florida in the aftermath of her mother’s death. They’re mourning and unsettled, but they were also haunted by her in life.

This was a mom who carefully packed delicious school lunches — but with an implicit message: “All that food, bought and prepared, just like the love that we were told was there for us to grab and have — it would be embarrassing and gross, pathetic, if we ever actually wanted, needed, asked for whatever sustenance or comfort it (either the love or food) might provide,” Jude tells us. Later she notes that the people with whom we share genes will “hurt us, maim us, leave us flayed open.”

So while Jenn, the oldest sister, tightly holds herself together by controlling everything, Jude, her sister Fred and her brother, George, have been unraveling for a while now. Their mother’s death merely gives them the chance to fall apart together.

This interview has been edited for length and clarity.

Q Jude is the narrator, but she’s somehow omniscient, able to tell us things her siblings felt or did that she couldn’t know. It’s an unusual form but really effective. How did you choose that?

A It was sort of my way to cheat. I love the first person, but I’ve come to be deeply devoted to a multifocal novel. So this is how I get to have my cake and eat it too?

I tell students one of the thrills of fiction is secret sharing, but a secret only feels important if it has weight for the person who’s receiving it. So I love the idea of the narrator telling a story for whom they have immediate and intense stakes.

Also, I think all gossip is us telling on ourselves. I wanted Jude to tell us she’s telling a story of her sister, but, of course, she’s telling us also the story of herself.

I was also playing with the idea of fiction, of telling a story. I was thumbing my nose a bit at autofiction. Of course, she can’t know what her sister’s sex life is like, but who cares? That’s what imagination is for.

Q Chekhov’s rule dictates that if you introduce a gun early on, it must go off at some point. You kept referring to Fred, who is emotionally frazzled, taking the gun with her when she went out. Were you consciously keeping the reader on edge by doing that?

A I love the idea of an object or an action as scaffolding that ultimately ends up being not that important. The gun was your red herring, although I did have it go off because that’s the rule. I’m excited by formal choices.

Q Were you at all tempted to break the rule and not have the gun go off?

A You’ve sort of caught me. I love thumbing my nose at rules, but I did feel here like I had to follow this one.

At one point, I thought the gun would be used on George, but what was interesting to me about writing the book was that I came to love George too much. I start from a place of being annoyed by all the characters and highlighting their most awful parts. But by the end, one of my directives for myself is that I love them all. I’m proud that almost every one of my friends who’ve read the book says George is their favorite.

But this might be my failing as a writer — I’m such a mushy person that at the end of the day that I couldn’t have the gun used on George even though I’d planned on it. I wrote a different book. I do know that some people are going to be really pissed by how the gun is used.

Q Fred is a novelist who writes about her family, but now Jude is the one telling us her story and acknowledging she is making stuff up. Is she to be trusted, or is she exaggerating for writerly effect?

A So much of the story is about how the stories that we tell about ourselves and one another cloud our vision and leave us with blind spots that keep us separate from one another. Jude has her story of her family, but because Fred has told the story of their family and made it something else, Jude, who has read all of Fred’s work — and said she felt she knew Fred better then before — is hijacking that because she has been told her family’s story back to her by Fred.

Q How biographical are the sibling and parent-child dynamics, emotionally if not factually?

A One of my favorite things to say about fiction is it’s not our job to tell the facts. It’s our job to say how it feels. I grew up in Florida. I’m the second of four children. Before my parents read it, the thing that made me nervous was the feeling in this book that did feel really true to me. I think we’re always wrenching from somewhere deep inside ourselves, and this was the deepest and hardest wrenching, and that all felt true.

Q The siblings’ mother is just infuriatingly awful, tormenting her kids. I could not find any empathy for her. Did you?

A I did come to love her in a way. She is not a good mom, but she’s a great lawyer, and I’m sure she’s good at other things. The word “mom” is a really hard word for her to live inside of, and that has real consequences. I wanted her to infuriate you, but I also think that she’s still a human and she deserves our empathy and sympathy.

Q One character tells Fred that her novel got “everything wrong” about her. Do you think Fred got it wrong or was that character simply hurt? Or did Jude put those words in her mouth because of her own hurt about how the family is portrayed?

A I had a novel that accidentally upset a friend in this way that I found surprising. There have been people I’ve been worried about hurting, but this was totally off my radar.

Anybody who has their story told back to them thinks the storyteller got it wrong. Jude thinks Fred got it wrong.

A friend who writes nonfiction says she once described someone as very beautiful. And the woman got mad, saying, “I’m more than beautiful.” When you see yourself in language on the page, you’ve been flattened, and that feels untrue, because you are more than anything that language can say. But that’s a lot of what this story is about.