Actress Ellen DeGeneres plays a bookstore worker in the just-released film The Love Letter.

And in real life, she's continued the role by acting as handseller for Don Miguel Ruiz's The Four Agreements: A Practical Guide to Personal Freedom and Toltec Wisdom.

During a May 19 appearance on Oprah, DeGeneres noted that she had "read a lot of good books" to deal with the depression that followed the signoff of her weekly sitcom. But she waxed particularly enthusiastic about Agreements, a self-help/personal growth title published by San Francisco's Amber-Allen Publishing and written by Ruiz, a Mexican-born, San Diego-based neurosurgeon who rediscovered the ancient teachings of his youth following his own near-death experience.

It's a book, DeGeneres urged on air, that "you gotta read."

Amber-Allen publisher Janet Mills already considers Agreements a steady success -- it has gone through five printings, and has about 40,000 copies in print since its original trade paperback publication in 1997.

But sales surged following DeGeneres's mention.

"Ingram usually has a demand of 200 copies a week for the book -- not even a week later, that count is up to 1300 copies," said Mills.

The book's rank on Amazon.com also jumped, from around #2000 to the mid-30s mark, and it now hovers in the 200 range. Oprah's Web site also features the book, along with the blockbuster Conversations with God, also mentioned on the show by DeGeneres. Distributor PGW reported quadrupled weekly sales in the superstores for The Four Agreements, which is also available in a Spanish-language edition from Amber-Allen, and a Peter Coyote-narrated audio is soon to come.

And the sales momentum could continue.

Mills has heard from acolytes of Ruiz (whose second book, The Mastery of Love, was released in March with a 10,000-copy first printing) that since the show, Oprah herself went into a bookstore to purchase a copy of The Four Agreements.

At press time, Mills couldn't confirm that rumor ("I'm praying"), but she had the pleasure of spotting another potential celebrity endorser when she used a frequent flyer upgrade to travel first class to last month's BookExpo America in Los Angeles. "Sharon Stone was on my flight and I was curious to see what she was reading," said Mills. "Imagine my delight when I discovered it was The Four Agreements."