Working under the direction of Dr. Arthur Kramer (WILLIAM DEVANE) who heads a Pentagon committee overseeing the project, and aided by veterinarian Sarah Kennedy (KIM DICKENS), lab technician Carter Abbey (GREG GRUNBERG), and data analysts Frank Chase (JOEY SLOTNICK) and Janice Walton (MARY RANDLE), the team has succeeded in making a gorilla invisible and then visible again.

Despite the inherent medical danger of doing so and without Kramer's permission or knowledge, Sebastian decides it's time to move on to stage three which involves turning a person invisible. Ever the brilliant egomaniac, Sebastian decides to be the human guinea pig. Their experiment is successful, but after several days of testing, data collection and pranks courtesy of the invisible man, the team realizes that they didn't make the correct calculations to return Sebastian back to visible form.

As they race to do just that, both the effects of the serum and the fact that he's isolated in their underground lab begins to make Sebastian mentally unbalanced. Realizing they have to pull the plug on the project and get Sebastian outside help, the team sets into a motion a series of events that will ultimately endanger their lives as the progressively unstable Sebastian loses his sense of morality but gains a warped sense of limitless power and will do anything to stop the others.

Although various people throughout time have contemplated the physical, as well as moral and ethical ramifications of being visually undetectable, the military has obviously been at the forefront of such efforts. Not only have they disguised their fighting units and equipment with clothing and markings designed to camouflage them, but they've also designed stealth aircraft that are invisible to radar and other detection devices.

Beyond corsets - the gastrointestinal nightmares from the past that were designed to make a woman's waist all but disappear - civilians have otherwise been left to the realm of science fiction for their invisibility fixes. From H.G. Wells' 1897 novel "The Invisible Man" to the 1933 Claude Reins/James Whale film of the same name, the dramatic notion of people becoming invisible has mesmerized the public for some time.

That's because such stories have tickled the reader's and viewer's imagination by making us wonder what it would be like to be invisible, as well as the thought that such a person could be watching or standing right next to you and you might not even know it.

Perhaps it's because the protagonist is invisible and thus, well, a bit hard to see, however, such stories haven't dominated the cinema - a decidedly visual medium -- particularly of recent. In fact, the last notable films featuring such invisible characters were John McTiernan's "Predator" from 1987 that put a fun and otherworldly spin on the old tale, and 1992's "Memoirs of an Invisible Man" that attempted to update the classic with humor - courtesy of Chevy Chase -- and new special effects.

Of course, the other problem in telling such tales on the big screen is that it's been a bit difficult to make such effects look real and credible. Until relatively recently, the method hadn't changed much from the old days of empty, but stiff clothing used to represent the invisible character's form and/or simply wrapping up the subject from head to toe in clothing to do the same.

With the state of the art special effects found in Paul Verhoeven's "Hollow Man," however, that's no longer a consideration. Featuring an eye-popping array of visual effects - many of which are seemingly accurate in recreating the inner workings of the human body and would probably make a medical school proud or even envious - the film is all flash, but unfortunately suffers from progressively dwindling substance and depth.

While it retains Wells' basic "what if" premise and related moral questions regarding invisibility, it proceeds to become just a variation on the classic cat and mouse suspense thriller where the "feline" here just so happens to be a invisible, homicidal character. As played with subversive gusto by Kevin Bacon, the titular character comments, "It's amazing what you can do when you don't have to look at yourself in the mirror anymore." While that's probably an accurate statement about losing one's inhibitions when faced with such a dilemma or opportunity, Verhoeven and screenwriters Andrew Marlow ("End of Days," "Air Force One") and Gary Scott Thompson ("K-911") don't take full advantage of the opportunities presented by such a sci-fi conundrum.

Sure, the character eavesdrops and spies on his cohorts, plays some practical jokes on them and sees how far he can get with the women when they can't see his roving hand or lust-filled eyes. He even briefly goes into the outside world where he scares some kids (in a funny scene that could and should have been accompanied by more similar ones) and terrorizes a woman (to what full extent we never know).

Yet, once such "fun" gets underway, the filmmakers decide to hole-up both the progressively deranged invisible man and what will soon be his victims in a locked down, underground lab area. While that makes for some relatively suspenseful moments - since the would-be victims can't see their attacker - it's nothing but a variation on that cat and mouse scenario that was executed far better in "Predator" and the early "Alien" films.

While the script deploys various tools for the hunted to use in trying to detect the killer - such as motion detectors, infrared visors and even the emission from fire extinguishers - and then has him figure out ways to defeat or circumvent such efforts - neither are particularly imaginative or inventive (in a crowd-pleasing way), and they don't do much for helping create the greater sense of urgency and suspense that the film needs.

It's also not clear why other obvious efforts were left out. For instance, early in the film, the titular character adversely reacts to the regular lighting in the lab due to the fact that his eyelids are now transparent. Yet, neither the filmmakers nor the hunted seem to remember that fact, a point one would think they would have used in trying to stop or at least hinder his efforts.

Of course, when one's dealing with such notions of invisibility, all sorts of related questions inevitably pop up. While we can generally accept the underlying principle that the researchers have figured out a way to defeat physics and achieve invisibility - through something they call a "bio-quantum phase shift" - they must still deal with other related "real world" issues.

Since Bacon's character must use a fingerprint scan early in the film to enter the underground lab, how does he get back in once he's left? Although his genes have been altered to render all parts of his body invisible, how come we don't see his food, water and other outside elements floating around inside his body (a point actually somewhat covered in the Chevy Chase film) or those regurgitated stomach contents as they splash into a toilet in one scene?

While such issues aren't huge or distracting problems, they should have been addressed to give the film more of an intelligent feel. Known more for attempts at delivering titillating entertainment to the masses, Verhoeven ("Starship Troopers," "Basic Instinct"), however, doesn't seem too concerned with that beyond some early related moments. That's a bit of a shame since by the time the cat and mouse material begins, we don't care about the monster that Bacon's character has become (or his victims for that matter).

That's too bad since it would have added greater depth to the proceedings. While on a basic level we understand why Sebastian eventually becomes unhinged and then deranged, a slower and more intelligent look at the transformation (such as with William Hurt's character in "Altered States") would have made for a more intelligent and thus fulfilling thriller.

Even so, and for what Verhoeven and his team are trying to accomplish, what's there does work to a degree, no doubt helped by the film's terrific visual effects. As provided by Sony Pictures Imageworks (under the supervision of Scott E. Anderson), The Tippet Studio (team efforts headed by Craig Hayes) and Amalgamated Dynamics, Inc. (Alec Gillis and Tom Woodruff, Jr. designed and created the prosthetic and mask effects), the visuals are nothing short of outstanding. While the film never explains the physical rationale behind why Sebastian and a gorilla disappear and reappear layer by layer (the skin goes first and then proceeds down to the bones, etc.), the effect is extremely cool to behold, as are most of the other related ones scattered throughout the production.

Unfortunately, the performances aren't quite as spectacular, and are generally typical for a film like this, although Bacon ("Stir of Echoes," "My Dog Skip") gives his character a bit more depth than one would expect (through nuances rather than anything really stemming from the script), at least during the first half.

While Elisabeth Shue ("The Saint," "Leaving Las Vegas") looks nice and adequately wears the women's survivor boots first broken in by Sigourney Weaver several decades ago, her performance isn't particularly notable, which also holds true for Josh Brolin ("Best Laid Plans," "The Mod Squad") as her lover and fellow researcher. The rest of the characters are just the of the typical fodder for the killer variety, and easily could have been switched, recast or removed without much ill effect.

Although we never know the military's motive in funding such invisibility research (a subplot that's underdeveloped and ultimately unnecessary) and the film jettisons the moral, psychological, and most every other "al" implication of such an occurrence in favor of straight out chills, many audience members will still probably get a kick out of what it offers.

Filled with great special effects and a decent cat and mouse finale, the film may improve on the Invisible Man story from a technical aspect, but doesn't really add anything more otherwise to make the film standout from similar adaptations that preceded it. That doesn't mean it's a horrible film, but instead ensures that it's not as good as it could have been. "Hollow Man" rates as a 5.5 out of 10.