Excellent TV tonight, National Geographic's Inside the Koran

Inside The Koran is on the National Geographic Channel, 9 to 11 p.m. Eastern.

Suppose you were strapping on a vest full of dynamite to blow up a market in Baghdad. Suddenly your cell phone rings -- it's your imam, telling you the Koran verse promising martyrs a reward of six dozen virgins has been misunderstood. Actually, your reward for blasting yourself to pieces will be a bunch of grapes. Do you still go through with it?

That's one of the many conundrums posed by "Inside The Koran," an excellent National Geographic Channel documentary airing Tuesday. Skipping nimbly past the twin pitfalls of political correctness and religious jingoism, Inside The Koran is full of penetrating insights into what it calls ''the world's most ideologically influential text,'' the holy book that guides a billion Muslims.

The question that drives Inside The Koran is the same one countless Westerners have asked as the tectonic plates of Islamic and Judeo-Christian civilizations have ground against one another with increasing violence over the past 30 years: How can Sufi pacifists and Sunni suicide bombers draw their inspiration from the same book? How can a woman be head of state in Indonesia, the world's largest Muslim nation, but not even permitted to drive in Saudi Arabia, the home of its holiest sites?

The broad answer is that the Koran, like any religious writ, is full of ambiguities, vague metaphors and even outright contradictions. (Which Bible verse do you prefer: the one in Leviticus that says adulterers ''must be put to death'' or the one in John that quotes Jesus saying, ''If any one of you is without sin, let him be the first to throw a stone''?)

"The Koran is like a big store, like a big supermarket,'' says one Islamic scholar interviewed in Inside The Koran. "In this book you are able to pick different answers. You are able to make peace according to the Koran. You are able to declare war according to the Koran.''

So the Koranic decree for women ''not to display their adornment'' is interpreted by some Muslims as requiring that women cloak everything but their eyes, blotting themselves out of the world like ninja warriors. Others believe it only requires the hair be covered. And the mother of one young college-educated Egyptian woman who has recently adopted conservative garb plaintively wonders if the whole business doesn't amount to putting words in Allah's mouth: "God could have said, 'Cover your hair.' It wasn't mentioned.''

Disputes about the necessity of head scarves may seem only a couple of degrees beyond arguing about how many angels can dance on the head of a pin. (Though women beaten by Saudi Arabian religious police for indecorous attire may disagree.)

But Inside The Koran does not shirk from pointing out just how insanely far some Islamic religious authorities are willing to push their Koranic interpretations. The unearthly screams of a little African girl undergoing religiously mandated female circumcision rank as some of the most horrifying moments ever witnessed on television. The burning eyes of a fundamentalist theologian who says a disciplined program of genital mutilation would solve a lot of the problems of the West run a close second.

Not just the interpretive meaning of the Koran but also the literal one is subject to dispute. Muslims believe the entire Koran was revealed to the prophet Mohammed by the angel Gabriel in the 7th Century. But it was turned into a book only after Mohammed's death, compiled from notes taken by his friends and family.

The most fascinating segment of Inside The Koran concerns scientific investigation of the oldest known manuscript pages, discovered in Yemen in 1972. They were written in the early eighth century without diacritical marks, the little dots and accents that can change not only the pronunciation of Arabic but also its meaning. Some scholars, the documentary reports, believe anywhere from 5 to 20 percent of the words in the Koran have been misidentified.

So the Koranic sentence that's been widely understood to promise martyrs an eternal romp with virgins — ''we have paired them with dark wide eyed maidens'' — could, with insertion of diacritical marks, actually be "we will make you comfortable under white, crystal clear grapes.''

The scholar who makes that point uses a pseudonym and is shown only in shadows, a wise precaution given that a Palestinian historian of Islam was thrown out a second-floor window by his students for similar statements. As Inside The Koran observes, tolerance for theological disputes within Islam has sharply declined in direct proportion to the growing influence of Saudi Arabia, home to the religion's small but radical Wahabi sect, and Iran, where Shia Islam reigns.

As an Egyptian woman who believes that the Koran does not require her to cover her hair says, "Fifteen years ago I could have engaged in a discussion with men of religion over that. Today it is almost impossible . . . If you say that, it is blasphemous.''