How do you produce an engaging two-hour biography of one of the most influential men in world history without showing his image?

The producers of "Muhammad: Legacy of a Prophet," a PBS documentary premiering Wednesday about the Arab desert trader whose religious experiences led to the founding of Islam, have smartly overcome this cinematic challenge.

Combining symbolic images from the desert landscape in which Muhammad lived almost 1,400 years ago, contemporary footage of Muslims visiting Islam's holy sites and, most importantly, interviews with American Muslims about what Muhammad means to them, the film offers an absorbing rendition of his life story.

It is a timely documentary, coming as Islam is under attack from within, by fanatics who distort its teachings, and from without, by those seeking a scapegoat for violent hot spots around the world.

Against an evocative original musical score, it relates how Muhammad, an illiterate but successful and well-liked merchant in the trading center of Mecca, initially believed he was going crazy when he began receiving what he later accepted as revelations from God.

It also recounts the struggles that he, his family and his early followers faced as he sought to spread these revelations and their message of monotheism, in a culture steeped in worship of many different idols. It was to discourage such idolatry that Muhammad forbade his followers to visually portray him in any way -- a ban most of the world's 1.2 billion Muslims still follow.

"Our original goal was just to tell the story about a man who changed the world," said Alexander Kronemer, the Baltimore filmmaker created the film with Muslim author Michael Wolfe. After last year's terrorist attacks, Kronemer said, "the program has taken on greater importance as the need for understanding Islam, and for American Muslims to speak for themselves, have both grown."

The film portrays Muhammad as a religious figure but also as the military and political leader he became as the beliefs of the expanding Muslim community threatened prevailing political and economic structures. In particular, Muhammad's message that all humans were equal in God's sight challenged the dominant concept of tribal affiliation.

The documentary takes up some controversial topics associated with Islam, including the status of women, jihad and the perception that the religion is anti-Jewish. Although these matters are discussed superficially, at least viewers hear explanations directly from Muslims themselves.

Four American Muslims -- none recent immigrants -- speak at length about Muhammad as an inspiring model of Muslim behavior and about their faith. The four include critical care nurse Najah Bazzy of Dearborn, Mich., who wears an Islamic head scarf, and Daisy Khan, a New York architect, who does not. The third is Jameel Aalim-Johnson, chief of staff for Rep. Gregory Meeks (D-N.Y.).

Kevin James, a convert to Islam and a recently retired New York City fire marshal, provides the film's most poignant moment, recalling his reaction to the Sept. 11, 2001, attacks.

"I just felt, oh, in the back of my head, please don't be Muslims doing this. And I just felt ah, I just felt sick," James says.

"What hurt me probably most of all," he continues, "was that here is a religion that I entered because of the universality. And the tolerance. . . . Yet these people who did that . . . were just so intolerant and so disregarding of their own tenets, that they could do something so horrific."

The film is not perfect. The narrator tells us there are "an estimated 7 million" Muslims in the United States, giving no indication that this figure is widely disputed.

Also, the film portrays Muhammad as a man who firmly insisted he not be confused with God and was just a human being. But while we hear of his self-doubts, we don't hear about any of his faults, which would have made him seem even more human. For example, Islam's holy book, the Koran, tells how an annoyed Muhammad once frowned and turned his back on a blind man for interrupting him.

Still, these are minor flaws in an enjoyable and informative film about a man who did indeed change the world.

The program airs at 9 p.m. Wednesday on Channel 22 and 8 p.m. Dec. 26 on Channel 26.

Najah Bazzy, a critical care nurse in Dearborn, Mich., is one of four U.S. Muslims featured in "Muhammad: Legacy of a Prophet," which airs Wednesday on PBS.Instead of images of Muhammad, which he forbade, paintings of the age and other depictions were used in the documentary.