No contemporary franchise has been more instrumental in recalibrating the action movie than the Bourne trilogy, with its two directors, Doug Liman (The Bourne Identity) and Paul Greengrass (The Bourne Supremacy, The Bourne Ultimatum), bringing an immersive, visceral approach that feels bone-crunchingly real yet as thrilling as any James Bond movie.
More thrilling, in fact, because when 007 was relaunched with Daniel Craig the producers brought their series into line with the Bourne movies, toning down the cheesy double entendres and precisely ordered martinis and embracing the reality of global terror, Orwellian satellite surveillance and vicious hand-to-hand combat.
Much of the Bourne series' success should be attributed to writer Tony Gilroy, who anchored the feverish direction of Liman and Greengrass to a storyline that tempered fantasy and hyperbole and emphasised character, logic and espionage in a high-tech world.
Gilroy now gets his own shot of Bourne glory, taking up directing duties from Greengrass, who along with star Matt Damon fled largely because they felt the series had come to a natural conclusion after Jason Bourne discovered his true identity and exposed Treadstone, the illegal CIA program in which patched-together soldiers were brainwashed into being assassins.
Gilroy's clever and largely effective solution to making a Bourne movie without Jason Bourne (there was never a question of slipping in a replacement actor) is to shuffle sideways - to imagine an even more sinister CIA plot running parallel to the chase for Bourne over the three previous movies.
That covert operation, called Outcome, involves enhancing the physical abilities of agents by altering their DNA through the use of drugs. Bourne was lethal but Jeremy Renner's Aaron Cross in the new movie is to the previous model of superspy what Usain Bolt is to every other sprinter in the world.
However, Bourne's exposing of Treadstone, which is recapped during the opening of The Bourne Legacy, means the CIA must move quickly to shut down Outcome because further revelation could bring the whole illegal edifice tumbling down. They do this not with the regulation leave-with-pay route but extermination.
When Cross gets wind that things have gone haywire since Bourne blabbed he, too, goes rogue, first making his way to a mountain hideaway where another agent is sitting on a supply of the drugs that not only keep them alive but tweak their physical and mental abilities.
When that goes awry Cross must find the scientist (Rachel Weisz) who has been responsible for giving him the medication that keeps him one step ahead of the enemy, which is now the United States government.
The Bourne Legacy will probably come under fire for lacking the propulsion of the previous movies, especially the last one, whose thundering metal-on-metal climax raised the bar so high for big-screen action that nothing has come close since.
Yet I was still fascinated from start to finish as the CIA heavy Eric Byer (a commanding Ed Norton) relentlessly tracks Renner's Cross and Weisz's frantic, disoriented scientist, using such a dizzying and disturbing array of technologies to zero in on the fleeing couple that it will make you think next time you use an ATM or pay for a parking ticket.
However, the new movie does lack the existential heft of the previous films. Renner is a fine actor and as physically accomplished as his predecessor but his character's motivation - to simply stay alive - is not nearly as interesting as Damon's Bourne, who was also struggling to unravel the secret of his identity and the extent of his crimes as well as exposing the criminality of his puppet masters.
Nonetheless, I still enjoyed jumping on the Bourne express for a fourth time, albeit one that slows down a little to take in the scenery - and why shouldn't it when the scenery is as lovely and talented as Rachel Weisz?