NEW YORK – A popular romance novelist who’s been criticized for allegedly lifting material has angered the biggest name in the genre: Nora Roberts.

A romance novel Web site, http://www.smartbitchestrashybooks.com, has posted numerous excerpts from Cassie Edwards’ novels and placed them alongside passages from magazines and nonfiction books that were found by using the Google search program.

Roberts, whose fiction has sold hundreds of millions of copies, told The Associated Press on Thursday that “it seems clear” Edwards acted improperly.

“Given the side-by-side comparisons I’ve read, it seems clear Ms. Edwards copied considerable portions of previously published work and used them in her books without attribution to the original source,” Roberts wrote in an e-mail to the AP. “By my definition, copying another’s work and passing it as your own equals plagiarism. As a writer, a reader and a victim of plagiarism, I feel very strongly on this issue. I’m not a lawyer, but I can’t see it as fair use, or fair anything when one writer takes another’s work.”

Both Roberts and Edwards are published by Penguin Group (USA), which on Wednesday defended Edwards, saying: “She has done nothing wrong.”

“The copyright fair-use doctrine permits reasonable borrowing and paraphrasing of another author’s words, especially for the purpose of creating something new and original,” according to a statement issued by Signet, an imprint of Penguin. “Ms. Edwards’ researched historical novels are precisely the kinds of original, creative works that this copyright policy promotes.”

Roberts said she has contacted Penguin to express her unhappiness, and told the AP that “I fully expect and trust it will be handled as it should be.”

“It’s a serious accusation, and the publisher needs to act responsibly and gather all possible information,” Roberts wrote, adding that she has never read Edwards’ books.

Edwards, interviewed earlier this week by the AP, acknowledged that she sometimes “takes” her material “from reference books,” but added that she didn’t know she was supposed to credit her sources.

“When you write historical romances, you’re not asked to do that,” Edwards said, speaking from her home in Mattoon, Ill. She then asked her husband to get on the phone. He told the AP that his wife simply gets “ideas” from reference books.

“She doesn’t lift passages,” Charles Edwards said, adding that “you would have to draw your own conclusions” on how closely his wife’s work resembles other sources.

One example posted on the romance Web site juxtaposes text from Edwards’ “Savage Longings,” a 1997 novel, with a passage from George Bird Grinnell’s “The Cheyenne Indians,” an ethnography originally published in 1928 and reissued in 1972.

From “Savage Longings”:

“The women who belonged to this society created ceremonial decorations by sewing quills on robes, lodge coverings, and other things made of the skins of animals. Snow Deer had told Charles that the Cheyenne women considered this work of high importance, and when properly performed, it was quite as much respected as were bravery and success in war among the men.”

From “Cheyenne Indians”:

“Of the women’s associations referred to the most important one was that devoted to the ceremonial decoration, by sewing on quills, of robes, lodge coverings, and other things made of the skins of animals. This work women considered of high importance, and, when properly performed, quite as creditable as were bravery and success in war among the men.”

Edwards has written more than 100 novels in the last 25 years and, according to her publisher, has more than 10 million copies of her work in print. She usually writes about American Indians, but has also written about pirates and the Civil War.

John M. Barrie, who helped design plagiarism detection software widely used by college teachers, told the AP on Wednesday: “Ms. Edwards’ unattributed use of other peoples’ work as her own definitely constitutes plagiarism.”

The president of the Romance Writers of America, Sherry Lewis, believes the excerpts “raise some questions,” but declined to say Edwards had acted improperly.

“It’s not clear-cut to me,” she said. “You can see similarities in the passages, but I’m not qualified to make that assertion.”