Roberts had been kicking around Hollywood for a few years when “Pretty Woman” came out, bringing a knowing, confident edge to supporting parts in TV series (including NBC’s “Crime Story”) and ensemble-driven features (“Steel Magnolias,” “Mystic Pizza”). This Garry Marshall trifle about a corporate raider (Richard Gere) who falls in love with a call girl (Roberts) sanded the rough edges off a much darker original script, creating a modern, wealth-and-fashion-obsessed Cinderella story. If one can pinpoint the exact moment when Roberts became a star, it would be the film’s shopping montage. It handed the film over to its female lead and put Gere in the same position as the moviegoer, staring slack-jawed at the sheer, innocent, mind-boggling cuteness of his soon-to-be great love — a fallen goddess who, the script helpfully informed us, had only been hooking for four days. The sequence was the heart of the film and the origin point of Roberts’ career as a leading lady and romantic fantasy object. The greatest testament to its impact is the number of subsequent films that included some version of it, including Robert’s follow-up. (Next slide, please.)

An early example of what’s now called “misery porn,” this glorified B-movie (adeptly directed by Joseph Ruben) potently (if probably accidentally) seems to pick up where “Pretty Woman” left off. Roberts plays a woman who’s a virtual prisoner of her husband (Patrick Bergin), a hateful yuppie swine who dresses like a “Matrix” character, lives in an immaculate modernist beach house, arranges every can in his pantry with the labels facing out, and mechanically violates our dear Julia while listening to Hector Berlioz’s “Symphonie Fantastique,” the music used in the opening credits of Stanley Kubrick’s “The Shining.” Julia escapes, adopts a new identity and briefly finds love with a sensitive, shaggy-haired drama teacher (Kevin Anderson), then liberates herself from her husband’s grip by shooting him dead during a home invasion. (She realizes he’s in the house when she opens the pantry and discovers that somebody has faced all the cans with the labels out! SCREEK SCREEK SCREEK!) As a movie, “Enemy” is no great shakes, but as a showcase for sheer star power, it’s hard to beat. The filmmakers surmised that viewers would be mesmerized and appalled by the very idea that some evil person would be mean to Our Julia — and they were right. The high point, yet again, is a music montage not too different from the one moviegoers had seen a few months earlier in “Pretty Woman”: Julia grinning, flirting and trying on hats to the tune of Van Morrison’s “Brown-Eyed Girl.”

Julia Roberts appears in just a few minutes of Robert Altman’s Hollywood satire “The Player” (1992), but they’re the right 10 minutes for a woman who had established herself as box-office gold, and one of the few women commanding salaries comparable to the era’s biggest action film stars. Roberts’ clout is the subject of a running gag: A pretentious English director (Richard E. Grant) keeps pitching the film’s slimy hero, producer Griffin Mill (Tim Robbins), on an anti-capital punishment jeremiad called “Habeas Corpus,” about an innocent woman executed for a crime she did not commit. He says he wants “no stars” because they would compromise the film’s realism. But the director’s partner, a shameless producer played by Dean Stockwell, keeps interjecting the names of just two possible leads, Bruce Willis and Julia Roberts — who, of course, show up in the final scene where Griffin and his studio colleagues watch the film’s finale in a screening room. Roberts does some of her best acting here, and with no words: just a resigned poker face. She’s playing America’s sweetheart — and America’s martyr. She’s perfectly cast.

Roberts’ off-screen melodramas eclipsed her screen adventures in 1991, when she abruptly called off her impending marriage to Kiefer Sutherland (her costar in 1990′s “Flatliners”), allegedly because she was having an affair with actor Jason Patric (which didn’t work out, either). While it wasn’t the first or last time that the actress’s love life would obsess the tabloid media, it’s notable for its seeming impact on her choices as an actress. As we’ll see elsewhere in this slide show, Roberts repeatedly appeared in films that were about the pressures and pitfalls of fame, the anxiety that comes from living life in the spotlight, and how celebrity tends to turn people into intimidating, slightly mysterious abstractions — not just to their fans, but to themselves.

“My Best Friend’s Wedding” is biographically significant for a couple of reasons. For one thing, it’s about a wedding, with Roberts serving as maid of honor for a handsome, likable guy (Dermot Mulroney) whom she always secretly hoped to end up with, and his damnably sweet fiancee (Cameron Diaz, one of many actresses who tried to usurp America’s sweetheart, with mostly limited success). For another thing, the film is about a wedding, for crying out loud — an on-screen event that one might have expected Roberts to avoid after the Sutherland debacle. The film intriguingly positions Roberts as a bulletproof pixie who can do no wrong (even when she’s doing wrong), playing a self-centered character who comes perilously close to playing the Jason Patric role in this story. In the end, she doesn’t get her heart’s desire (just a ten-times-hotter gay best friend played by Rupert Everett). But she wears defeat fetchingly, as a kind of low-impact martyrdom. As William Goldman wrote in “Adventures in the Screen Trade,” the first rule of Hollywood screenwriting is, “Give the star everything.”

Playing off her reputation for dumping guys and breaking off engagements, Roberts plays a woman who repeatedly does just that. “Pretty Woman” costar Richard Gere rejoins her, this time playing a USA Today columnist who tries to write a definitive piece on this odd, compelling woman and ends up falling for her. A mostly lame, forgettable film (directed by “Pretty Woman” helmsman Garry Marshall), but it fits into Roberts’ growing tendency to appear in films that, at first glance, play like straightforward comedies or ensemble dramas, but, as it turns out, are fascinated by the media, the images it constructs, and what those images do to people’s minds.

Released the same year as “The Runaway Bride,” this is modest, often beguiling romantic comedy is partly about a bookshop owner falling in love with a visiting American film star. But it’s mostly about the world’s obsession with Julia Roberts, an actress who lives her life under a microscope and dreads bringing loved ones into the petri dish. Roberts’ character, Anna Scott, is a Julia Roberts-type shooting a film in the titular London neighborhood. She resents that her fame puts a scrim between her and her loved ones, and is pleasantly stunned when the bookshop owner, William

This entry is about two things: a movie and an acceptance speech. “Erin Brockovich” was director Steven Soderbergh’s successful attempt to bring indie-film grit to a little-person-against-the-system legal thriller. The film won her an Academy Award as best actress. The press treated it as a naturalistic, risky change of pace for Roberts, but have you watched the film recently? Erin is a total pain in the ass, a raging narcissist, and she treats everyone, including her boss and co-workers, rudely (even humiliating a co-worker for being overweight and badly dressed). And with rare exceptions — most of them involving the heroine’s biker boyfriend (Aaron Eckhart) — the film seems to be OK with this. “Erin Brockovich” is basically a late ’80s/early ’90s Tom Cruise film, except the main character is female. When Roberts won the Oscar, we saw an unfortunate glimpse of that roughshod brazenness: Holding the statuette, she informed the orchestra conductor that she would be running over her allotted time and that she was not to be played off. And she wasn’t.

In 2002, Roberts reteamed with director Steven Soderbergh (“Erin Brockovich”) for one of the director’s trademark postmodern hall-of-mirrors projects, a funky digital video riff on acting, impersonation, truth and lies. The actress plays two roles: a movie star appearing opposite fellow movie star Blair Underwood in a major motion picture, and a reporter in the film-within-a-film that the pair are shooting. Underwood is interviewed about acting; Roberts does the interviewing. It’s in this film that Julia Roberts officially became “Julia Roberts,” an abstract concept faintly resembling the great movie star fans once thought they knew. Like Keyser Soze, you had to wonder if she even existed. Soderbergh’s 2004 film “Ocean’s 12″ — a sequel to his 2001 remake “Ocean’s 11″ — took the self-reflexivity one dizzying step further. Roberts reprised her role as the title character’s ex-wife, Tess Ocean; this time the team’s convoluted plot revolves around Tess’ eerie similarity to Julia Roberts. For some reason, Julia Roberts is not even remotely credible when playing Julia Roberts.

Perhaps the ultimate Julia Roberts part: Charlotte is a mentor, a martyr, a mother, and the secret puppet master helping the titular swine gain confidence in himself and become a big star — a fine alternative to a fate predicted by a barnyard sheep, who tells Wilbur he’s going to be killed and eaten at Christmas. Charlotte saves Wilbur by emblazoning meaningless slogans (“Some pig” “Radiant”) across her web; in essence, Wilbur is the nascent star and she’s the media and P.R. machine puffing up his image and saving his bacon (rim shot). Charlotte is also God the Mother, finally dying beautifully, knowing that her surrogate son is well taken care of. If that’s not a movie star role, there’s no such thing.