It's not every day that mathematicians and fiction writers invite each other to their respective department colloquia.

But math, says author David Leavitt, is at its heart an art form.

Leavitt, author of the new and highly acclaimed historical novel "The Indian Clerk" and co-director of the creative writing program at the University of Florida, will speak at Cornell's Center for Applied Mathematics' weekly colloquium Oct. 19 at 3:30 p.m. in B11 Kimball Hall. A book signing and refreshments will follow at 4:30 in 102 Thurston Hall.

Like other artists, mathematicians divide their time between two distinct worlds: the imagined and the real. The difference, Leavitt says, comes in the degree of separation between the two.

"For writers, the imaginative world bears closer resemblance to the physical world," he says. For mathematicians, the worlds -- the human and the utterly abstract -- are as remote as any two things can be.

In a phone interview from Gainesville, the author said this will be his first math colloquium -- but probably not his last.

"The Indian Clerk" tells the story of the brilliant and enigmatic mathematician Srinivasa Ramanujan, a 25-year-old port clerk in Madras, India, with only a rudimentary education -- and his collaborations with Cambridge mathematician G.H. Hardy, who brought him to England to work on one of math's most vexing mysteries: a potential key to understanding prime numbers known as the Riemann Hypothesis.

"It was incredibly daunting," Leavitt said of writing the novel. "But it was also an exciting opportunity to immerse myself in the past. These guys were absolutely obsessed by this subject matter, and I became completely fascinated by it."

The source material was plentiful, from archived correspondence to accounts by students and others from the period. "I read an enormous amount of stuff -- anything that looked like it would be pertinent, I read," he said.

Steve Strogatz, the Jacob Gould Schurman Professor of Applied Mathematics and director of Cornell's Center for Applied Mathematics, invited Leavitt to the colloquium after reading the book.

"The story of Ramanujan is such an incredible, dramatic story," says Strogatz. "Everyone in math has heard the story and wondered about it."

Mathematicians, he said, will appreciate the book's meticulous detail. "Leavitt is super accurate. He's really good," Strogatz says.

But the real accomplishment, he adds, is the story around the math -- of relationships, colonialism, guilt. "Even people who are not mathematicians would appreciate the dramatic tension," Strogatz says. "I love the writing. He has a beautiful gift for language."