"It's a blow," said Lorraine Shanley, a partner in the consulting firm Market Partners International Inc., who earlier this week watched former Alaska governor and Republican vice presidential candidate Sarah Palin promote her book on Ms. Winfrey’s show.

"Oprah Winfrey has supported many authors, and her book club has had a huge impact on America's reading habits," added Ms. Shanley. "She made Faulkner a best seller again. She also promoted an eclectic group of authors and created publishing successes for many commercial writers."

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Over the years, the book club has helped to bring the works of well-known writers such as Maya Angelou, Toni Morrison and Cormac McCarthy to even broader audiences. The show has also introduced writers such as Edwidge Danticat to millions of readers.

"Other than a book being turned into a popular movie nothing brings readers to a book like Oprah," said Dawn Davis, editorial director of the Amistad imprint of News Corp.'s HarperCollins Publishers. (News Corp. also owns The Wall Street Journal.) "She brings a variety of readers to a variety of books. Her impact is immeasurable."

"On December 27, 2008, Herman Rosenblat admitted to fictionalizing portions of his life story, including how he met his wife. Based on this admission, the publisher of his forthcoming memoir — Angel at the Fence — canceled plans to print his book."

This summer, David Wroblewski got the phone call every writer dreams about: Oprah Winfrey was on the line to chat about The Story of Edgar Sawtelle, his debut novel about a mute Wisconsin boy and his dog.

"We talked about the book and her dog Sophie — her 'once-in-a-lifetime' dog," Wroblewski tells USA TODAY. (Winfrey's beloved cocker spaniel died this year.) Friday, Winfrey announced Sawtelle as her latest book club pick. "I think this book is right up there with the greatest American novels ever written," declared Winfrey, who will host a live webcast with Wroblewski. Published June 10 with a first printing of 26,000 copies, the book has 1.25 million in print, thanks to an infusion of 945,000 Oprah's Book Club edition copies.

The book has topped the best-seller list on Amazon.com virtually from the moment Winfrey's choice was revealed, and it is the fastest-selling pick ever at Barnes & Noble Inc., according to a statement issued Thursday by Winfrey.

It's also a record shipment in a four-week span for any book by Penguin Group (USA), which has published such million sellers as Elizabeth Gilbert's "Eat, Pray, Love" and Ken Follett's Winfrey-endorsed "The Pillars of the Earth."