New York - Even for an Oprah Winfrey book pick, "A New Earth" has been a sensation.

About 3.5 million copies of Eckhart Tolle's spiritual self-help guide have been shipped since Winfrey, host of "The Oprah Winfrey Show," announced her selection four weeks ago.

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."

Brian Tart, president and publisher of the Penguin imprint Dutton, told The Associated Press that a key factor was the upcoming Web seminars featuring Winfrey and Tolle, to be held for 10 consecutive Mondays starting March 3.

"Oprah herself has committed 10 weeks to talking to the author, and people from all over the world will be able to participate," said Tart, who added that more than 500,000 people, from more than 100 countries, have registered for the seminar.