About 10,000 copies of a book about John Walker's road to a Taliban training camp are now on the market, the publisher says.

The books were shipped to retailers Monday, despite a written warning from a member of Walker's defense team alleging the book contained defamatory material, said publisher Rhawn Joseph of San Jose-based University Press, California.

Nearly 12,000 orders for the 224-page paperback book, John Walker Lindh: American Taliban, have been received so far, Joseph said Thursday.

Walker attorney George Harris had warned in his letter, sent March 12 in response to promotional descriptions of the book, that "publication would be at your peril." The letter contended "the book is grossly and outrageously false and defamatory," but did not provide specifics.

Kerry Efigineo, a spokeswoman for the Walker defense team, said Harris had no further comment.

Copies of the libel threat were sent to Amazon.com, Borders Inc. and Barnes & Noble, all of which have the book listed on their Web sites.

"We had repeatedly made contact with these guys, trying to work with them," Joseph said of Walker's lawyers. "We called them up and left a message saying, 'We'll show you a copy of the book. We'll even let you print your rebuttal."'

Joseph said another edition with footnotes would be released later.

Walker, 21, is awaiting trial in Virginia on charges he conspired to kill Americans abroad by aiding terrorists. He was captured late last year in Afghanistan after an uprising by Taliban prisoners in which a CIA officer was killed.