WHO: Gwendolen Gross

WHAT: Signing "The Orphan Sister"

WHEN: 7 p.m. Wednesday at Bookends (writing workshop and signing); 7:30 p.m. Thursday at Barnes & Noble (signing).

WHERE: Bookends, 211 E. Ridgewood Ave., Ridgewood; 201-445-0726 or book-ends.com. Barnes & Noble, 765 Route 17 south, Paramus; 201-445-4589 or barnesandnoble.com.

FOR MORE INFORMATION: gwendolengross. com.

The one time she went to a fortune teller, a psychic whispered this promise: You will have twin girls.

"I didn't," Gwendolen Gross said during an interview at her Ridgewood home. "But I thought, 'What would that be like?' "

Pair that bit of curiosity with this unusual chapter from her family history …

"My grandmother had triplet uncles," Gross said, "and looking at the pictures, two of them look identical and one looks different. And I didn't know if that was possible. And nobody could tell me. … So I asked a friend of mine who's a medical writer. I said, 'Is that possible?' She said, 'Oh yeah, polyzygotic twins. I knew a set like that.'

Her new novel, "The Orphan Sister," is about a similar set of triplets. Its focus is a young woman named Clementine — the sister who does not look like the two others. The sister who is not married, not pregnant and not blessed with a first name that starts with the letter "O."

Gross spent three years on this book, digging into the life of that third sister, chronicling her quest to find what is missing.

"Most people are always looking for a pair," Gross said. "That's sort of the way we're programmed – to look for an other. It doesn't mean that they're incomplete people without that. But they're looking for that. And I think being born with an other who is not your romantic partner but is somebody who in some ways knows how to finish your sentences both belittles individuality and adds to it."

Gross has two sisters and one half-sister. She is married with two children. Some material writers cull from their own nest, but Gross reached outside her neighborhood to find a setting for this novel.

"I knew somebody when I lived in San Diego who was from Princeton," Gross said. "And I remember thinking about how orderly her life was. I don't exactly remember what it was, but there was some scandal in her family that made me think, 'There's this exterior and the interior life.' The interior life is full of self-doubt and agony and desire for love and attention that everybody has. The dog has that. Everybody has that. Everybody has that desire for love and attention. And money doesn't make that any less."

When she isn't writing or chasing after 12-year-old Jacob or 9-year-old Carina, Gross is usually teaching. She works with different writing groups, including one in Ridgewood. Most students, she said, are now older than she is.

"So we talk about point of view, we talk about tense and we talk about real time versus habitual time," Gross said. "And I try to give them exercises. Right now they're all supposed to write a sex scene, and they have a really hard time with that. But it doesn't mean that everything is going to end up in their books."

The teaching element does help her writing. "So much," she said. But she also warns her students of the perils of taking up writing full time.

"It's hard," Gross said. "You have to love it enough to do it. But if you have too much time to do it, I think people get bogged down in time."