What, if anything, do <EM>Star Wars</EM>, <EM>Mission: Impossible,</EM> and <EM>Jaws</EM> have in common? What, if anything, do Star Wars, Mission: Impossible, and Jaws have in common?

What is the formula for blockbuster-movie success? And how does it differ from the recipe for disaster? Boffo! Tinseltown's Bombs and Blockbusters, an HBO documentary premiering tonight at 9 pm/ET and based on the new book Boffo! How I Learned to Love the Blockbuster and Fear the Bomb, by Variety editor-in-chief and former studio exec Peter Bart  explores those much-asked questions by way of A-list talking heads and fantastic clips from films both great and... so-so.

Bart says that  especially as cohost of AMC's Sunday Morning Shootout (think Ebert & Roeper meets Meet the Press)  he has often been asked to identify the ingredients that lead to box-office bizillions. Alas, as countless filmmakers have seen over the decades, there is no easy answer, if any at all. "The most important common denominator," Bart tells TVGuide.com, "is that every hit reflects the vision of one strong individual who was willing to accept all the disdain and animus and anger and rejection and see the damn thing through  only to find that when the picture opened, there was still more disdain and anger and rebuke."

The releases of the Boffo! book and documentary are timed perfectly, here at the start of the summer movie season. As such, TVGuide.com asked Bart to weigh in on the box-office surprises to date, and the highly anticipated films still in wait.

"Certainly, Poseidon, on the downside, was a surprise," Bart opines. "Warner Bros. has always felt that [it can] almost put blockbusters on an assembly line. But everyone was skeptical about whether Poseidon would resonate well." Everyone, in this case, was right. "It opened OK here and OK overseas, but on the downside, Poseidon may be the least successful wannabe blockbuster."

Sandwiching Poseidon's waterlogged debut were offerings from Hollywood's two Toms  Mission: Impossible III and The Da Vinci Code  each of which met expectations, albeit to different degrees. "Surely, Mission: Impossible III didn't perform as well as the first two, and perhaps Tom Cruise's image was a part of the problem," Bart notes. "[Tom Hanks'] Da Vinci Code has been the most successful film so far, in terms of international acceptance, because that's not a typical summer picture. It's a drama, not a shoot-'em-up."

As Bart brings up "Tom Cruise's image" and "problem" in the same breath, we ask if there is a temptation to update his Boffo! book with a chapter on the "outside factors" that can affect a film's performance. "It's such an imponderable area," he says. "You almost need to mobilize the resources of a market-research company in order to find out how, for example, Mr. & Mrs. Smith was a big success, and how [the real-life headline-making of its own stars, Brad Pitt and Angelina Jolie] all worked in that instance.

"I've never seen anybody measure the public impact of Tom Cruise's television appearances or his religious beliefs," Bart continues, "but if you did a chapter like that, you should arm yourself with a lot of data, because everybody's got an opinion."

The Boffo! HBO documentary features plenty of candid insights from the likes of George Clooney, Brian Grazer, Sherry Lansing, Danny DeVito, Peter Bogdanovich, Morgan Freeman and Tom Rothman. In fact, looking back on what is widely regarded as the first blockbuster, Jaws, it is detailed how Steven Spielberg's film drastically and at the last minute changed, apparently for the better, all because the robotic shark repeatedly wasn't ready for its close-up. That's right  Jaws was what it was because of what wasn't seen.

Boffo! also offers some uncomfortable moments, particularly when the bomb-word gets dropped. "When we started this," Bill Couturié, the film's director, shares with TVGuide.com, "one of the first things I said to Peter was, 'Talking to people about blockbusters is a no-brainer, but people talking about their flops...?' This is Hollywood. It's going to be a bit tougher." Indeed, even a revered and award-winning thespian like Morgan Freeman was literally unable to vocalize what went wrong with The Bonfire of the Vanities, one of the biz's biggest bombs. Says Couturié, "Here's this Oscar-winning guy, one of the most respected actors on earth, the movie is 15 years old, and he could barely get a word out about it. It was still that hard on the guy."

Adds Bart, "The psychology of failure is odd. Brian Grazer is one of the wealthiest and most successful producers of all time, but he feels that Cinderella Man was a terrible blight on his career. By any normal standards, Cinderella Man was very successful and it did well with the critics, but he felt it didn't fulfill its expectations. It's all a matter of expectations."

So what does Bart expect from the summer's remaining releases? Which films are all insiders' eyes on? "Certainly, Pirates of the Caribbean [Dead Men's Chest] is the biggest gamble ever taken by Disney," he observes. "I mean, you're talking somewhere between 250 and 350 [million dollars] for the two sequels made simultaneously. To watch the success of that [will be interesting]. Will there be a whole new genre of movies based on theme-park rides? That would be somewhat disturbing."

And what of Superman Returns, which flew into theaters June 28 while weighed down with a supposed $300 million budget? Bart recalls the very tough sell he had back in his day with Michael Keaton as Batman. "Basically, Warner Bros. didn't want to make that movie," he shares. "They thought it was ridiculous, that the comic-book audience wouldn't move over." Ah, but they did, and even with film newcomer Brandon Routh in the title role, Superman Returns should be able to avoid being box-office Kryptonite. "[Casting] doesn't make a difference," says Bart, "because they feel that the star is the franchise."

Then again, as Boffo!'s numerous opinionators point out over and again, nothing should ever be predicted in a business where an action-packed Mission can be faced with Impossible goals, while the march of some goofy Penguins can instead enchant a nation. Hollywood is littered with hits and misses, as well as scores of blockbuster wannabes that instead were bombs that went off in people's faces. "Success is not a process where everyone applauds you going in and applauds you going out," Bart points out. "Usually they do quite the opposite."