More than 1,500 audiocassette tapes taken in 2001 from Osama bin Laden's former residential compound in Qandahar, Afghanistan, are yielding new insights into the radical Islamic militant leader's intellectual development in the years leading up to the 9/11 terrorist attacks.

Flagg Miller, an assistant professor of religious studies at the University of California, Davis, and the first academic researcher to study the tapes, will present his preliminary observations in a lecture at the Center of Modern Oriental Studies in Berlin on Sept. 18. The first research paper stemming from Miller's study of the tapes will appear in the October issue of the journal Language & Communication.

"Bin Laden did not start out at the top of this movement. He had to earn his way there, build his credibility," said Miller, a noted scholar of Arabic. "These cassettes help to tell us how he did that."

The collection offers "unprecedented insight into the debates going on among bin Laden's allies and critics in the five years leading up to the September 11th attacks," Miller said. "They also show his evolution from a relatively unpolished Muslim reformer, orator and jihad recruiter to his current persona, in which he attempts to position himself as an important intellectual and political voice on international affairs."

The audiocassettes, along with a number of videotapes, were first acquired by a CNN producer and Afghani translator in the weeks following the Taliban's evacuation from Qandahar on Dec. 7, 2001. After the FBI declined stewardship of the tapes, CNN turned the collection over to the Williams College Afghan Media Project, headed by anthropologist David Edwards. Edwards contacted Miller, a linguist and cultural anthropologist who studies the roles of language and poetry in contemporary Muslim reform in the Middle East. The audiocassettes are now at Yale University, where they are being cleaned, digitized and described; the process will take several years to complete.

"In trying to understand bin Laden's own intellectual formation, analysts to date have had to rely exclusively on what he has revealed in statements made to world audiences, or else on what has been reported about him by his former teachers and associates, family members, journalists and various political representatives," said Miller, who is indexing the tapes and has listened to excerpts from many of them. "No equivalent 'library' of his has yet come to light."

The tapes date from the late 1960s through 2000 and feature more than 200 speakers from more than a dozen countries in the Middle East, Indian subcontinent and Africa. The speakers, identified on cassette labels, include prominent scholars as well as some of al-Qaida's most important strategic thinkers and operational leaders. The recordings include sermons, political speeches, lectures, formal interviews, exchanges between students and teachers, telephone conversations, radio broadcasts, recordings of live battles and Islamic anthems, as well as trivia contests and studio-recorded audio dramas.

Twenty of the audiocassettes contain recordings of bin Laden; 12 of these include material previously unpublished in any language, according to Miller.

Among his early observations, Miller has found that bin Laden took many years to identify a single consistent message or political platform. For example, in bin Laden's early recordings he sometimes called non-Muslims throughout the world "dogs," while on other occasions he advised his listeners to engage civilly with Western embassies and consulates by writing letters and organizing public demonstrations to protest Israel's treatment of Palestinians.

However, bin Laden consistently identified the United States, especially through its support of Israel, as his number-one enemy, even before Iraq's invasion of Kuwait and the massive augmentation of U.S. forces on the Arabian Peninsula, Miller said.

The audiocassettes shed light on how the fight against the Soviets in the 1980s shaped bin Laden. The recordings also confirm him as a man who regards his homeland, Saudi Arabia, as corrupt, believes that Islam has been perverted by ruling Arab leaders across the Middle East, views Muslims as victims of global persecution and sees himself as a reformer who is setting Islam on a better path.