In the beginning was the Dude. And the Dude was with God, and the Dude himself was kind of godly, if you're into that sort of thing.

In his right hand the Dude carried a cocktail, and in his left, a bowling ball, and all of his ways were righteous and mellow altogether. And Cathleen Falsani saw the Dude, and saw that he abides, and was so smitten that she wrote a book about his creators.

"The Dude," for those not versed in the films of the Coen brothers, is Jeffrey Lebowski, the slacker-saint anti-hero of the 1998 movie "The Big Lebowski." To Falsani, though, the Dude is more than a movie character -- he's a role model. He's patient with his friends, tolerant of his enemies and kind to his landlord. In other words, the Dude abides, "takin' her easy for all us sinners," as one character puts it in "The Big Lebowski."

For Falsani, a self-described "sometimes churchgoing Catholic-turned-Baptist-turned-freelance-Episcopalian," that line rang some bells. "I'm a Christian," she said, "so when I think of the Dude, I think of him as Jesus."

So Falsani, an author and columnist for the Chicago Sun-Times and Religion News Service, began combing through the Coen brothers' unique oeuvre -- the Coeniverse, she calls it -- for spiritual and ethical themes. The result is The Dude Abides: The Gospel According to the Coen Brothers , published by Zondervan.

By some force of cosmic kismet (Falsani calls it Providence) The Dude Abides hits bookstores just as the Coens are releasing their most explicitly religious film to date. "A Serious Man," scheduled to hit Utah theaters Oct. 30, is about a Job-like figure who turns to rabbis for explanation after his life goes awry.

Falsani, who saw the movie at the Toronto Film Festival, said it takes place in the Minneapolis suburb and middle-class Jewish milieu in which the Coens were reared, and may be their most personal film to date.

During the past 25 years, the Coens have written, directed, and produced 14 utterly original and enigmatic films, including Oscar-winners "Fargo" and "No Country for Old Men." Some, such as "Raising Arizona" and "O Brother, Where Art Thou?" are cartoonish comedies; others, such as "Miller's Crossing" and "The Man Who Wasn't There," are deadly serious and violent.

"Their films are so different in subject matter and period and style, the 'rug that ties the room together,' is spirituality," Falsani said, echoing a famous line from "The Big Lebowski."

But the Coens' films rarely are overtly religious. Falsani acknowledges that others will draw different lessons -- or no lessons at all -- from the same scenes.

"Their films are like life itself, full of questions with little didacticism," Falsani writes in The Dude Abides . "Still, the Coens leave the door to interpretation (spiritual, artistic, stylistic and otherwise) wide open."

Falsani strides boldly through that door, drawing up a list of 14 "Coenmandments" and inferring the "moral" of each of the Coens' movies.

For example, she says, the 2008 film "Burn After Reading," is about what happens when people follow their desires instead of God's laws; "No Country for Old Men" probes the nature of evil; and "Barton Fink" is the cautionary tale of a man whose head obscures his heart.

As children, the Coens dutifully attended Hebrew school every Saturday and celebrated their bar mitzvahs at 13, they have said.

"Judaism was a central part of the home we grew up in," Ethan, 52, told Playboy magazine in 2001. (Older brother Joel turns 55 in November.) But the Coens say they no longer are religious. In his senior thesis at Princeton University, Ethan wrote that belief in God is "the height of stupidity."

"I do think they are deeply suspicious of organized religion and false piety," Falsani said, a suspicion that often carries over into the Coens' films. The most sanctimonious characters -- such as the ruthless Bible salesman of "O Brother, Where Art Thou?" -- often are the most immoral.

Don't pay too much attention to what our characters say, the Coens seem to imply, just watch what they do -- an ethical stand Falsani attributes to their Jewish background.

Take Marge Gunderson, for example, the plucky and pregnant heroine of "Fargo," a film Falsani judges "perhaps the finest example of a Judeo-Christian morality play in all of American cinema."

Played by Oscar winner Frances McDormand, whose father and sister are Disciples of Christ ministers (she also is Joel Coen's wife), Marge risks her life -- but not her Midwestern politeness -- to bring murderous kidnappers to justice.

In many ways, Falsani said, Marge embodies the highest spiritual goals in the Coeniverse. "Just be decent, and take'er easy, man."