"Donnie Brasco" was like no mob movie that came before it. Based on a true story, that of FBI undercover agent Joseph D. Pistone, who spent years infiltrating New York's Bonnano crime family, its mobsters were decidedly unglamorous petty criminals, guys who had to resort to breaking into parking meters to make their monthly nut. It was directed by an Englishman best known for a Hugh Grant romantic comedy. Its hero, who never fires a gun except on the FBI firing range, was played by Johnny Depp (then best known for quirky, vulnerable man-child roles) and his mentor was played by Al Pacino (as a tired, rumpled mafioso, about a million miles from his Michael Corleone or Tony Montana). That it worked at all was miraculous, especially considering how different it might have been with its initial star and director. The result was a modern classic that made a grown-up star out of Depp and influenced the tone of mob dramas for years to come (particularly TV's "The Sopranos," whose depiction of street-level mob politics owes a debt to "Donnie Brasco"). As the film marks its 15th anniversary (it was released on February 28, 1997), here are true tales of what went on behind the scenes, including one star's impulsive wedding, and how the real Pistone braved a contract on his head to ensure that the movie portrayed accurately the mob world he uncovered.

1. In 1976, Pistone was chosen to go undercover as purported jewel thief Donnie Brasco because he spoke fluent Italian, was familiar with the mob (having grown up in Paterson, N.J.), and because he claimed the ability not to perspire under pressure. The undercover operation was supposed to last six months; it lasted almost six years.

2. Pistone's undercover work resulted in 200 indictments and 100 convictions. It also led the Mafia Commission (the body that oversees all the New York organized crime families) to kick out the Bonnano family over the security breach.

3. Paradoxically, being booted from the Mafia Commission actually helped the Bonnano family. While the Mafia Commission Trial of 1985-86 put much of the mob hierarchy behind bars, the Bonnanos were exempt from prosecution and were able to consolidate power.

4. A $500,000 bounty was placed on Pistone's head. To this day, he travels in disguise and with a concealed firearm. He generally avoids cities with a large Mafia presence, though he did spend time in New York as a paid consultant on the "Donnie Brasco" movie. And he appeared, undisguised, in one of the featurettes among the extras of the "Donnie Brasco" Extended Cut DVD released a few years ago.

5. Louis DiGiaimo, who was a childhood acquaintance of Joseph Pistone and who helped him as a consultant on his book, was also a casting director for Barry Levinson. So it was the "Rain Man" director who got the first crack at the film rights to "Donnie Brasco: My Undercover Life in the Mafia"

6. At first, Stephen Frears ("The Grifters") was to direct, and Tom Cruise was to star. But the project was postponed because of the 1990 release of "Goodfellas." The producers felt the film would be seen as a knock-off of Martin Scorsese's based-in-fact gangster drama.

7. Paul Attanasio had been a go-to screenwriter for Levinson, working with him on TV crime drama "Homicide: Life on the Street." He'd written Levinson's "Disclosure" as well as the Oscar-nominated screenplay for Robert Redford's "Quiz Show." So he was a natural to adapt Pistone's book.

8. By the time the film was shot in 1996, the director was now Mike Newell ("Four Weddings and a Funeral"), making his Hollywood debut. Levinson and DiGiaimo were producers. Johnny Depp had replaced Cruise. Al Pacino, always the only choice for Benjamin "Lefty" Ruggiero, was still aboard.

9. Pacino and Bruno Kirby (as fellow mob soldier Nicky Santora) had both appeared in 1974's "The Godfather Part II," though not together. In the sections set in early 20th century Manhattan, Kirby had played the young Peter Clemenza, who helps the young Vito Corleone (Robert De Niro) rise to power and becomes one of his closest associates. Pacino, of course, played Vito's son, latter-day godfather Michael Corleone, in the sections set in the late 1950s.

10. Newell went to Brooklyn social clubs to meet and drink with real wiseguys. In one club, he saw a huge jukebox with nothing but Sinatra records. There was a hand-lettered sign below the payphone warning that the phone is bugged. "I saw how they never trust each other," the Englishman recalled. "They didn't trust me. I talked funny. I looked funny."

11. Attanasio learned how to capture mobsters in conversation by listening to FBI wiretap tapes.

12. For Depp, the role of Pistone/Brasco marked his transition out of the precious man-child roles (in movies like "Edward Scissorhands" and "Benny & Joon") that had been his trademark. "He was becoming a man, not a boy," Attanasio said. "We captured that on film. It was incredibly exciting."

13. Pistone praised Depp for his mimicry. Watching the film with his eyes closed, he said, "I could not tell if it was his voice or mine. He was right on the money."

14. Pacino never got to meet the real Lefty, and much of the character is his own creation, including the rumpled jogging suits and the sad little hat. Newell and Pistone both hated the hat, but Pacino insisted on it as a way into the character. According to Pistone, the real Lefty was a sharp dresser who never wore a hat.

15. As in the film, Lefty really did have a pet lion and could be spotted walking him on the streets of Brooklyn.

16. At the end of the film, it's implied that Lefty has been marked for death for having brought FBI infiltrator Pistone into the mob's inner circle. In real life, however, it was Dominic "Sonny Black" Napolitano (Michael Madsen's character) who paid the price; he was shot to death and had his hands cut off. Lefty Ruggiero would have been killed too, had the FBI not arrested him before a hit could be carried out. Once in FBI custody, Ruggiero refused to turn state's evidence and was sentenced to 20 years in prison. Because he refused to rat, the contract on him was canceled. After serving 11 years, he was paroled in 1992 when it was discovered he had terminal lung cancer. He died in 1994, a little over a year before the film was shot.

17. It was during his downtime on the Miami portion of the shoot that Madsen whisked his girlfriend, DeAnna, off to Ocho Rios, Jamaica, and impulsively married her. Talking to The Guardian years later, he recalled, "DeAnna was driving me insane. She wanted to drive into town and get jerk chicken, and I wanted to stay at the hotel. I needed a plan to keep her at the hotel, so I said, "Let's get married!" She had a gold bikini on, I had my 'Donnie Brasco' wardrobe. It wasn't planned at all, I had no idea. It wasn't till the jerk chicken thing came up. And you should have heard Al when I told him about it. He was disgusted with me." Nonetheless, the Madsens have been married for 16 years.

18. Playing Pistone's long-suffering wife, Anne Heche filmed all her scenes during the last three weeks of the shoot, when everyone else was tired. Which worked, since Heche's role consisted largely of confronting Depp over the toll his undercover work was taking on their family life. In real life, however, Pistone hardly ever got to see his family, who had been moved across the country nine months into the operation. For years, his only contact with them was by phone.

19. The film cost a reported $35 to produce. It was a modest hit in America, grossing $42 million, and it did even better oversea, earning $83 million.

20. "Donnie Brasco" earned one Oscar nomination, for Paul Attanasio, for Best Adapted Screenplay

21. One of the odder promotional items sent to critics was a box of facial tissues covered with stills from the movie. Whenever you lifted the lid to grab a tissue, a chip inside would play Depp's lengthy speech in which Pistone explains to a FIB technician (Paul Giamatti) the many meanings of the phrase "Fuhgeddaboudit."

22. The Brasco story was also the source of the 2000 CBS TV drama series "Falcone," starring Jason Gedrick as Pistone. Copyright clashes kept the series from calling him by his alias Donnie Brasco; in the series, his cover name was Joe Falcone.

23. Pistone wrote several other books about his undercover work and the Mafia sociology he observed. He produced the 2006 movie "10th & Wolf," based on a related case in Philadelphia. In 2008, he adapted his book "The Ways of the Wiseguy" into an autobiographical one-man play. He was played onstage by his nephew, Joey Pistone.

24. Madsen has cited "Donnie Brasco" as one of his favorites among his own films, though he grumbles about his fee. "Great film, sure, but not a payday. Al and Johnny got all the money. There was none left for me."

25. Lefty Ruggiero's granddaughter, Ramona Rizzo, is one of the stars of VH1's current reality series "Mob Wives."