Friday, it comes, the final detonation of the cultural blast that left millions of foreheads metaphorically imprinted with lightning-bolt-shaped scars. “Harry Potter and the Deathly Hallows — Part 2” is the final installment of the leviathan eight-film series based on J.K. Rowling’s monumental best-selling novels.

Since 2001, the Potter movies have been both a financial freight train and a jobs program for all of Britain’s aging character actors. The books have become almost holy.

I’m holy. Holey, Fred, geddit?”

(Don’t worry, your kids get it.)

It is a franchise that became a movement. A revelation. An era. Friday’s opening is the last chapter in a saga that has affected — at least via “Saturday Night Live” spoofs, mentions on university syllabuses, and in religious sermons — the world’s collective oversoul. Doled out incrementally over 14 years, it taught us patience.

“What has ‘Harry Potter’ meant?” asks Emerson Spartz, who founded the fan site as a home-schooled 12-year-old more than a decade ago. “What is the meaning of life?”

Harry Potter, the Boy Who Lived, the vanquisher of the evil Lord Voldemort. His 1997 appearance enthralled a generation of readers and then schooled them, semester by semester, at Hogwarts School of Witchcraft and Wizardry. His adventures were penned by a single mom who lived her own adult fairy tale: She got lucky, got famous, got really attractive and got richer than almost everyone but Oprah.

Harry Potter keeps ending. There were stories about the end when Rowling finished the last book in early 2007, when her readers read the last book in mid-2007, when the last movie finished filming last year, and now . . . now what?

Now the numerical analysis begins, because non-fans often confuse what Harry Potter meant with what Harry Potter cost. It cost caped moviegoers more than $6 billion in ticket sales — a third more than all 22 James Bond movies combined. It cost readers the equivalent of 450 million copies, compared with 80 million for the beloved “Chronicles of Narnia.” It costs $80 a ticket for each visitor to Orlando’s Wizarding World of Harry Potter theme park, where fans purchased a total of 2 million Butterbeers. It costs $46.99 to buy a naughty-wizard costume in Gryffindor colors on

Despite the proliferation of stuff, it’s not about the stuff.

Harry Potter manufactured a decade in which nearly everyone could share one reference point. Be it through mocking or devotion, everyone knew what it was, which was rare in a fractured age of 500 cable channel options.

“It’s big. It’s huge. It’s going to be so huge. It’s the end of an era. I’m so excited, I’m going to die,” Paul Dergarabedian sighs. “I don’t know what I can say anymore.”

Dergarabedian studies box office numbers for He’s who you call when you want to know what movie data mean. He’s running out of ways to describe Harry Potter and the Massively Bloated Box Office. “To be this relevant? This beloved? I’ve never really seen anything quite like it.”

In the cottage industry of Potter analysis, no superlative is too super, no grandiosity is too grand, no pie in the sky is too high — though the limits have been tested: Harry Potter saves book sales! Harry Potter saves reading! Harry Potter saves us all!

“It’s hard to pin down causes,” says Sunil Iyengar, the director of research at the National Endowment for the Arts, but there was an increase in adult reading habits between 2002 and 2008. The largest were in the 18-to-24 demographic, precisely the readers who were weaned on Harry.

Of course, that time mirrored the rise of e-readers, of Facebook groups and fan-fiction portals. Booksellers benefitted from Harry Potter, but Harry benefited from the cross-promotional world (the Boy Who Sold!) into which he was born. People loved “The Lord of the Rings” when the series was released in the 1950s, but it would be decades before they could buy Gandalf’s sword online.

“We’re so proud,” says Kyle Good, a vice president at Scholastic, Harry’s U.S. publisher. “It’s crossed cultures, it’s crossed generations, it’s become embedded in this society. . . . We think every child should read ‘Harry Potter.’ We think it should be a rite of passage.”

“My parents read them to us when we were little,” says Carmen Rucker, 17, of Charlottesville. “Those were the stories we were raised on. I was convinced that I was going to get my Hogwarts letter when I turned 11.” Her sister confessed she’d thought the same thing. Two little girls, waiting for the owls to bring letters announcing their admission to wizard school and for a magical train to take them there.

What would this generation look like without Harry? Glasses would be less round. No one would parade around in long, striped scarfs. No Muggles. No Britishisms. No hipsterish college students ironically playing Quidditch on the quad.

No vast democratization of bookworminess — the thrilling assertion that books were cool, and so was make-believe, and elves, yes, so were elves.

No patience, maybe. “Harry Potter” installments have been doled out as slowly as a morphine drip, each one savored and analyzed (let no one who has read an online debate over Rowling’s copyright fret about the critical-thinking skills of today’s youth). One might argue that the most valuable legacy that “Harry Potter” will leave behind is the gift of anticipation, and the ability to wait in line. Potterphiles, accustomed to midnight-release parties, will grow into adulthood and suddenly the DMV will become serene.

“The era that we’re in is driven by instant gratification,” says Melissa Anelli, who chronicled Potter fandom in “Harry, a History.” “ ‘Harry Potter’ was a world in which we were forced to put everything down, and wait, and listen, and bask in all that.”

She saw the first movie in the District while here on business, alone in an unfamiliar city. She saw this final film at the London premiere, a special guest invited to stand along the red carpet. Now she’s in Florida, where she helped organize an annual fan conference. This year, it will be structured not as a convention but as a graduation. The program is a yearbook — leather embossed with foil, marking the time they are leaving behind.

And what of those new fans, the ones who will turn 8 or 9 every year and never realize what it was like to have to wait for hours at Barnes & Noble?

“I have read the seventh book five times,” says Adrian Hall, who is 9 and lives in Falls Church. He discovered the books last year. His favorite is “Deathly Hallows.” “I have it with me right now,” he says. “I like to give it a rest in between readings to sit there and imagine what happened. J.K. Rowling is a very good author.”

Is it over now, this collective moment? Not really. Not at all.

“Deathly Hallows” is the last official, visual representation of the series but, like Dumbledore’s phoenix rising from the ashes, the end represents new beginnings.

Last month, Rowling announcedPottermore, a not-yet-unveiled Web site whose Twitter feed has close to 170,000 followers despite having 10 tweets. Pottermore has promised to expand the Potterverse, with backstories on minor characters — how Harry’s piggish aunt and uncle first met, how Professor McGonagall once loved a Muggle.

“What we’re going to be getting is J.K.’s text,” says Heidi Tandy, the woman behind Fiction Alley, a well-known fan-fiction site. “Just her text, word for word.” That means that, for the first time in a long time, fans will have new, original material to look forward to. New characters to play at conferences. New romances to imagine. The books have ended, the movies are ending, but true fans have always known that Harry Potter really lives in hearts, not on pages or screens.

“ ‘Harry Potter’ has everything,” says Spartz, the MuggleNet founder. He’s now 24, lives in Chicago and runs a successful ring of community Web sites. “It has good versus evil. Love, sex and war. Right and wrong. Tough moral dilemmas. J.K. Rowling was providing moral guidance to an entire generation of readers. There is no important question left untouched.”

He pauses, pondering the question that launched his meditation.

“How has ‘Harry Potter’ impacted my life? For over a decade, ‘Harry Potter’ was my life.”