In a brief introduction to PBS’s ambitious new series, “America at a Crossroads,” about the rise of global Islamist terrorism, host Robert MacNeil describes the experience of working on the program as “clarifying” and says he hopes it will prove equally so for the viewer. Perhaps Mr. MacNeil means “clarifying” in the sense that a migraine is clarifying — “I want this headache to go away!”

For people trying to navigate a way through it, radical Islam is the pea-soup fog of political and religious ideologies. Indeed, PBS itself has become lost in the mists after canceling one of the projected episodes in the series, “Islam vs. the Islamists,” due to disagreement over what constitutes a “moderate” Muslim.

That still leaves us with an immense body of work — 12 hours in all — fulfilling one of public television’s mandates, namely to educate the public on matters of pressing concern. For this we should be grateful.

Nonetheless, the fog sets in early during Sunday’s two-hour opener, “JIHAD: The Men and Ideas behind Al-Qaeda,” when Mr. MacNeil refers to Al Qaeda’s perversion of “the peaceful and noble religion of Islam” only to note, 20 minutes later, that “the Prophet Muhammad was not just a spiritual leader like Jesus, but a soldier and a statesman commanding armies and fighting battles.” Images of charging warriors and torch-lit 7th-century Muslim armies then fill the screen. There seems no escaping the fact that war, or jihad, was an essential component of the religion from the start.

Sunday’s episode is an informational tour de force that provides a detailed overview of the careers of Osama bin Laden and his deputy, Ayman al-Zawahiri, along with an examination of the Muslim Brotherhood in Egypt, the rise of Nasser and pan-Arabism, the psychological effect of the Arab defeat by Israel in 1967, and the war against the Soviets in Afghanistan. There is also a fascinating detour into the years (1948–50) spent on a scholarship in Colorado by the “father of Islamic fundamentalism,” the author Sayyid Qutb, who was encouraged by his colleagues in Egypt’s Ministry of Education to visit America in the hope that he would become less anti-Western.

Instead, sporting a Hitlerian mustache, Qutb grew increasingly repulsed by church dances, the lasciviousness of American women, and, bizarrely, the American mania for mowing lawns. The result, as Fouad Ajami points out, is that Qutb “left America much more antiwestern than ever before.” In this sense, he was not only a theorist of Islamic fundamentalism, but a precursor of its deadliest practitioners, such as the westernized Mohammad Atta.

Near the end of the episode, Gwynne Roberts, a television producer who interviewed Mr. bin Laden in 1996, recalls being told that within 10 years there would be a world war stretching from China to Afghanistan to the Middle East to North Africa and into the West itself. “I think it’s a prophecy that has come true,” Mr. Roberts adds. We also learn that Mr. bin Laden has now fulfilled all the religious mandates required of him, which include asking President Bush and Vice President Cheney to convert to Islam, should he decide to detonate a nuclear bomb in America.

With that in mind, you may decide to skip “America at a Crossroads” and watch “Voyage of the Lonely Turtle,” immediately preceding the series on PBS, before tucking in early with a warm cup of cocoa and a good novel.

If not, Monday through Friday PBS will show two one-hour episodes of “Crossroads” per night, usually conjoined in the manner of a slightly fractious marriage. Monday’s episodes — “Warriors” and “Operation Homecoming: Writing the Wartime Experience” — contrast the actions of American soldiers in Iraq with the attempts of some to give their experiences literary expression. The first is more matter of fact and gung-ho (the soldiers, like those documented in George Packer’s “The Assassins’ Gate: America in Iraq,” are for the most part remarkably impressive), while the latter gives vent and artistic shape to their understandable fears.

The cruelest coupling comes on Tuesday, when “Gangs of Iraq,” a look at the homicidal militias destroying the country, is paired with “The Case for War,” in which Richard Perle has the task of retroactively defending the decision to invade. He gets in some good shots, but loses on points.

If this series has an overall message, it is that to respond to Islamist aggression — even on the scale of September 11, 2001 — is futile, since Islamists will never go away and never stop fighting. It also argues that to wage war is to fall into Mr. bin Laden’s hands: Everything he does is designed to draw Americans into the Middle East, Afghanistan included, so as to weaken our armies and reify our reputation as imperialists. The alternatives are therefore either to combat radical Islam through international police work (the John Kerry approach) or, as we saw in the British reaction to Iran’s kidnapping of its naval officers, to grovel and plead in order to keep the “peace.”

“Europe’s 9/11,” one of the best episodes, focuses on the Madrid bombings of March 11, 2004. It also illustrates the limitations of police work, since the Spanish police had no idea what was coming despite having some of the principal terrorists under surveillance. When ETA, the Basque terrorist group, was thought to be behind the attacks, Spaniards demonstrated in force. When the bombings were discovered to be the work of Muslims, however, they attacked their own government and blamed Spain’s valuable but very modest contribution to the war in Iraq. There were no mass demonstrations against the terrorists themselves, and no demonstrations of any kind by Spanish Muslims against the Islamists in their midst.

“Europe’s 9/11,” which airs Wednesday night, is paired with a documentary about America’s own Muslims. While many of the documentaries in the series were farmed out, this one is the work of PBS’s most trusted hands: Mr. MacNeil, Ray Suarez, and Judy Woodruff, all of whom take a studiously see-noevil, hear-no-evil approach. They seem to want us to believe that radical Islam is a problem that afflicts practically every corner of the globe except these United States. Since I can encounter curt-bearded fundamentalists two blocks from my apartment, this strikes me as myopic. True, we do not have the kind of Muslim alienation and violence seen in France, but there are signs pointing in similar directions: Increased politicization following the attacks of September 11, 2001, and children who are more radical than their parents. (“Islam vs. the Islamists,” the suppressed episode, argued that radical Muslims in America and Europe are creating separatist societies to be ruled by sharia law.)

Another strong episode is “A Different Jihad: Indonesia’s Struggle for the Soul of Islam.” The title is misleading, since the soul of Islam is Arabian if it is anything. The Indonesians’ more laid-back approach is under increasing threat (the 2002 Bali bombings, for instance) from swelling ranks of radicals outraged by the native “Miss Transvestite Indonesia” competitions among other local delights, and who claim that “when our religion is being brutally attacked, we have the right to fight back.”

But then, what don’t Islamists consider a “brutal attack” on their faith? Sayyid Qutb, after all, was outraged by church dances and lawns. What would he have thought if there’d been leaf-blowers around?

bbernhard@nysun.com