Tess Gerritsen admits she occasionally hears voices in her head.

But it’s just her characters talking to her.

Gerritsen, a best-selling suspense writer who lives in Camden, will be talking about how she created two of her most popular heroines, Jane Rizzoli and Maura Isles, at the fourth annual Maine Festival of the Book. The festival begins Friday night and runs through Sunday.

“My process, really, is just sit down and start writing and see if they’ll talk to you,” Gerritsen said. “There are writers who will do character sketches. They’ll do long, long pages of clues to the (character’s) personality, and I’ve never done that. I think I kind of go by instinct, and a lot of it is very mysterious.”

Gerritsen and fellow best-selling fiction writer Anita Shreve will open the festival at 7:30 p.m. Friday at the University of Southern Maine’s Abromson Center by talking about writing and the writer’s life.

Gerritsen said she enjoys such appearances because she gets to meet fans and interact with other writers.

“When I go on tour,” she said, “I meet a lot of readers, but I don’t often get the chance to hang out with other writers as well. It’s fun to hear what they have to say.”

It’s support from well-known authors such as Gerritsen that has put Maine’s Festival of the Book on the national map, says Sarah Cecil of Maine Reads, the nonprofit group that organizes the festival and supports other local programs that promote literacy.

“The fact that we’ve had four Pulitzer Prize winners in the first three years is big stuff,” Cecil said. “I find that when I talk to people who have put on other book festivals that are considerably older, they’re like, ‘How do you get such good authors so early on?’

“I think a lot of it has to do with people who have connections to Maine that are really great writers. We’ve been able to tap that really nicely, and are grateful for those writers and their generous help with the book festival.”

Reaching out to all kinds of readers has also been key, Cecil said. The idea of a book festival can seem dry, so Maine Reads works hard to make the discussions lively, bringing in authors that appeal to many audiences and reading levels.

Another enticement: Except for the first night, which costs $10, everything is free and does not require tickets.

Readings and discussions will be running all day Saturday at the Abromson Center, with topics ranging from writing novels to historic preservation. Comic book artist Jay Piscopo will be hosting a cartoon workshop for ages 7 to 12 at 11 a.m., and from noon to 2 p.m., about 30 authors will hold court at a Book Signing Bonanza, where fans can meet favorite authors.

Twenty-somethings tend to flock to the annual Poetry Party, which is “always a wild, fun scene,” Cecil said. The event, hosted by Port Veritas, will be at 7 p.m. Saturday at the Constellation Gallery, 511 Congress St.

Biography will be one of the hot topics. Mark Griffin, author of “A Hundred or More Hidden Things: The Life and Films of Vincente Minnelli” (Da Capo Press, $15.95), will discuss what he learned about the famous director of “An American in Paris,” “Gigi” and other classic films at 11 a.m. Saturday. He may also be showing a short documentary that he recently screened at the Museum of Modern Art in New York that features audio clips of Kirk Douglas, Lauren Bacall and George Hamilton describing what it was like to be directed by Minnelli.

The sleeper event may be an appearance by Anne C. Heller, a New York-based magazine editor and journalist, at 1:30 p.m. Saturday at the Abromson Center. Heller just wrote a biography, “Ayn Rand and the World She Made” (Nan A. Talese, $35), that has been getting a lot of attention.

“Ayn Rand – some people hate her, some people love her,” Cecil said. “People are passionate about Ayn Rand and ‘The Fountainthead’ and ‘Atlas Shrugged.’ This is Anne Heller’s first book, and it was featured on the front page of the New York Times Book Review.”

Tess Gerritsen’s appearance will be taped by a film crew from TNT, which is launching a new show this summer called “Rizzoli and Isles,” based on characters from eight of her crime novels. The show stars Angie Harmon of “Law & Order” fame and Sasha Alexander, who appeared in “Mission Impossible III.”

Seeing these characters, whose voices originated in her head, suddenly end up on the TV screen is “kind of weird,” Gerritsen said.

“I was there to see the filming of the first episode, and it was really a lot of fun to see,” she said. “They weren’t exactly what I had envisioned, but you go with the talent.”

Then she laughed.

“And, of course, they’re way more beautiful than I ever imagined.”

Staff Writer Meredith Goad can be contacted at 791-6332 or at:

mgoad@pressherald.com