A little less than 10 years ago, a curious new show called “Wicked” started drawing crowds at the Curran Theatre in San Francisco. Even then, its creators knew it was something special. They were right: their prequel to “The Wizard of Oz” is now a member of musical theater’s small but elite club of perpetual blockbusters.

The Broadway production, which opened October 30, 2003, is approaching its 10th anniversary and its 4,000th performance, and its popularity is showing no signs of waning; houses are routinely sold out. Currently it’s the 12th longest-running show in Broadway history.

A production at the Pantages Theatre in Los Angeles lasted almost two years in 2007-09 and was the town’s most coveted ticket for most of that time. “Wicked” has returned to L.A. and O.C. several times, but its nearly month-long upcoming visit to the Segerstrom Center for the Arts beginning Feb. 20 isn’t a case of producers’ wishful thinking. The last time it played in the 3,000-seat Segerstrom Hall, in 2011, it broke box office records.

Surprisingly, “Wicked” didn’t seem destined for success at first. It failed to impress two powerful constituencies: critics and theater professionals.

The Broadway debut received mixed reviews, and “Wicked” was snubbed at the 2004 Tony Awards. It was nominated for 11 Tonys but won only three: Idina Menzel captured the best actress award for her portrayal of misunderstood green witch Elphaba, the story’s heroine, and the show nabbed best scenic design and best costume design. But it lost in the big categories, best book, best original score and best musical, to “Avenue Q.”

How did a musical seen as a middling effort by the pros become a blockbuster of “Phantom”-like proportions? And what magic combination of ingredients has given it the gift of enduring popularity?

“It has an appeal across the generations,” said Paul R. Laird of the University of Kansas, a respected musicologist and author of “Wicked: A Musical Biography.” “It tells a very compelling story about friendship between teenage girls, which makes it very popular with that age group.” And to older people, a musical that engages with and expands upon L. Frank Baum’s famous story, “The Wizard of Oz,” carries an irresistible attraction as well, Laird said. “It effectively taps into what I think is the most important American fantasy story of all time.”

“Wicked” also touches upon themes that have proven popular throughout the history of American theater, Laird said. “You can go back to musicals over the last 70 to 80 years and find these same themes: female empowerment, the challenges of being an outsider. Think of ‘My Fair Lady’ or ‘The Sound of Music.'”

Another reason for “Wicked’s” success. Laird said, is its meticulous craftsmanship. It was put together carefully and painstakingly by the perfect combination of talents, and its birth was long and laborious.

The perfect creative team

“Wicked” is based on “Wicked: The Life and Times of the Wicked Witch of the West,” a clever piece of pseudo-history by Gregory Maguire that explains the back story to Baum’s fictional land of Oz. It was published in 1995.

Hollywood was interested, but Maguire’s book was a difficult vehicle to transform into film. Dark and violent, filled with serious examinations of adult themes, it was a challenge, according “Wicked” producer Marc Platt in a Register interview before the Pantages production.

“We developed a couple of drafts of the screenplay, and Demi Moore’s company was co-producer on it. She and her partner were interested in the material, but the project never took off,” said Platt, a Hollywood producer who was then president of production at Universal Studios. “It was somewhat dense. It took a lot from the book, all of which is interesting but not all of which is cinematic.”

Platt was fascinated with the parts of Maguire’s book that dealt with the relationship between Oz’s two famous witches, Glinda and the Wicked Witch of the West, when they were young women. The Wicked Witch, named Elphaba by Maguire, is a smart and high-spirited but misunderstood girl who’s self-conscious about her bright green skin. Glinda the Good Witch (or Galinda, as she was then known) is portrayed as pretty and popular but ambitious and vain. Their friendship and personalities change as they room together at a school that will teach them the tricks of their craft.

“The most interesting idea to me was the relationship between these two young women, and the distances each had to travel to be self-aware and be friends in the truest sense of the word,” Platt said.

Platt was unsure how to reinvigorate the project. “Then one day I got a call from Stephen Schwartz and he said, ‘I know you have the rights to this story, but did you ever consider making it a musical?’ The moment he said that, a light bulb went on in my head. I thought, ‘That’s it!'”

Schwartz, a respected Broadway and Hollywood composer (“Pippin,” “Godspell,” “Pocahontas,” “The Prince of Egypt”), had discovered Maguire’s book during a Hawaiian vacation. “It’s the kind of thing that appeals to me,” Schwartz said. “A lot of the work I’ve done over the years involves taking familiar stories or characters and spinning them around and looking at them from a different point of view.”

Platt brought on board Winnie Holzman, a respected Hollywood writer who created the TV series “My So-Called Life.” The trio collaborated intensely for months at Platt’s small cottage on the Universal back lot, writing story details on color-coded menu cards. Schwartz developed musical leitmotifs for major characters. “It was like working on the most complicated puzzle in the world,”‘ he recalled.

Several readings took place at Universal Studios. It was there, in front of his film-world colleagues, that Platt first got an inkling of the show’s emotional power.

“At the end I looked over and saw this line of film execs with tears coming down their faces. My friend Ed Zwick (director of ‘Glory’) said, ‘Marc, everything you’ve dreamed will come true.'”

“I’ve studied ‘Wicked’ for years, and what’s most impressive is the care and detail with which it’s constructed,” said Laird. “Nothing is random or out of place. It’s one of the best-crafted musicals ever written.”

Contact the writer: 714-796-7979 or phodgins@ocregister.com