Offhand, how old would you guess Liam Neeson is? Judging from the characters he has played in his latest movies, including Bryan Mills in "Taken" (2008), and Colonel Hannibal Smith in "The A-Team" (2010), you might think he's middle aged; 45, maybe? 50? No. He is 58.

His recent films have all trended toward action and psychological thriller, genres that he has always dabbled in, though they have not characterized his career by any means. He thrives in romances and dramas as well, so when he does take on an action role, he is usually chosen for the dimension that he adds to the role of the hero. He's like James Bond, if Bond chose to settle down and become a family man.

And now that he's getting older, it is my belief that he should begin to avoid action roles and continue to take advantage of his talent in other genres. Like Brosnan and Connery in their later years, Neeson is aging past his action movie prime. He has done surprisingly well considering his actual age; as I mentioned, he seems a lot younger than he actually is.

Despite this, in his most recent action/psychological thriller flick, "Unknown," Neeson is unmistakably starting to show his age. He is looking haggard, and whenever you wince for the action hero during fight sequences, it seems that it's time to hang up the action hero hat for good.

This film, of the lost/stolen identity/amnesia variety, seems like a kind of cross between "Taken" and "The Bourne Identity," plot-wise. The main thing preventing "Unknown" from being essentially the same as "Taken" is that that it is directed by Jaume Collet-Serra, famous for "House of Wax" and "Orphan" (both horror/suspense films). Coming from this background, Collet-Serra steers "Unknown" to suspense town, rather than to the absurdist action territory occupied by "Taken" under the direction of Pierre Morel, a director known for his cinematography work on the "Transporter" series.

In the film, Neeson plays Dr. Martin Harris, a biologist supposedly visiting Berlin for a professional scientific conference. When his taxi crashes into the Spree River and Harris wakes up from a coma four days later, his identity appears to have been stolen by an imposter. His wife (played by an impassive January Jones) won't acknowledge him, his associates don't appear to recognize him, and he has no documentation to prove himself.

Thus begins Harris' quest to get to the bottom of this unusual and alarming situation, and to do it he must avoid an insidious organization inexplicably hell-bent on his demise.

Where "Unknown" edges dangerously close to "The Bourne Identity" is in its use of memory-loss, including a history of clandestine espionage and an essentially pitch-perfect imitation of Bourne's amnesic visions.

Furthermore, and as further reason that Neeson seems more youthful than he is, both "Unknown" and "Taken" center around Neeson's characters' relationships with younger women—a plot point that isn't totally significant, but seems strange considering its consistency. In "Taken" he's out to save his daughter, and here, he's trying to recover his considerably younger wife while simultaneously developing a relationship with another woman, who is also young.

The relevance of this trend is that what "Unknown" ultimately amounts to is a sort of mixed pastiche that takes various elements from other films—there's even a Da Vinci Code-esque use of code breaking—and in doing so dilutes the film as its own entity. This shortcoming is demonstrated by the film's rhythm, which jolts awkwardly between action sequences and longer, calmer episodes of dialogue.

Despite the fact that Neeson is over the hill as a physically imposing action star, he plays the lead well, and is supported by an able cast, the standouts of which include Frank Langella as a collegue of Harris', and Diane Kruger as Gina (Harris' second young love interest).

Overall, "Unknown" is not a disappointment. I wouldn't watch it if you've seen any of the "Bourne" movies recently though; "Unknown" might seem like a cerebral but fatigued imitation.