Here's something to think about. Agent 007 had a childhood. He didn't spring fully formed from MI6 mythology with a gun in his hand and a taste for fastidiously composed martinis. He had fears and insecurities like other children.
These revelations, which emerge in Skyfall during a couple of gaps in the action, are a measure of just how far James Bond has come since Daniel Craig took over the character. Roger Moore and Pierce Brosnan, with their lacquering of easy charm, would never have been able to make anything credible out of the idea of Bond as a kid, let alone a lonely kid. Nor would Sean Connery - he looked as if he left home for a bachelor apartment as soon as he could crawl.
But the sense of reality permeating Craig's Bond intensifies with every film. The grooves in those sculpted features are looking very much like worry lines these days. And in this film, the vexing question of age is woven into the plot. For the first time, Bond is feeling his years - a problem shared by Judi Dench's M, who is forced to confront hers. They have a new boss, and he's tackled both of them on the frightening concept of retirement.
This makes it a distinctly different Bond film. All the usual ingredients are present - the ingeniously extended action sequences, the travel porn, the gadgets, the bizarre villain and the Bond girls - but the central relationship is the one between 007 and M. And if this combination of numbers and letters makes it sound as clinical as a mathematical equation, that's weirdly appropriate.
It's not exactly a surrogate mother-and-son relationship. In the opening sequence, she takes ''a calculated risk'' that almost gets him killed. But their wry and wary respect for one another is analysed as it's never been before - in a terse sort of way. Neither likes to waste words.
Craig's is an introverted Bond - another innovation. His emotions are as tightly buttoned as his suits. Everything about him is compact, efficient and purposeful. His walk is symptomatic. Lacking the loping grace of his taller predecessors, he walks fast, with his elbows stuck out. There's no vanity in it, and no wasted movement. Everything about it announces his seriousness.
And that makes sense. The Bond movies were born in the anti-establishment '60s, when the espionage business was not being taken seriously. So the high-camp, high-style approach was perfect. Now, post-September 11, 2001, a little more substance is required, and Craig is delivering.
Even so, it's time he lightened up. While he shows every sign of enjoying his flirtation with Naomie Harris as his fellow field officer, she's the one who does most of the bantering - and the seducing. He can't seem to take his mind off work, which, I suppose, is fair enough since the plot puts NATO's entire network of international agents at risk of exposure and certain death unless he can find and capture Javier Bardem. And here we do have some traditional high-camp tomfoolery.
Bardem's creation plays like a black comic parody of his sadistic assassin from No Country for Old Men, with a few new touches, one of which is a peroxide wig. Using the alias Silva, he's a former MI6 operative with a grudge against M and an army of thugs to help him settle it, and his silky manner covers a murky reservoir of self-pity. He also has some of the film's wittiest dialogue, the effect of which is mordantly enhanced by his Spanish accent.
The action moves swiftly between Turkey, London, Shanghai and Scotland, starting with Bond chasing one of Silva's men through the streets of Istanbul. It's the same neighbourhood Liam Neeson ripped up recently in Taken 2, so there's not much novelty value in it, but it is artfully choreographed and involves the usual dizzying array of vehicles. The climax comes when Bond is shot, topples from the top of a train, plunges down a waterfall and is given up for dead. And I'm not spoiling anything because all this happens before the titles come up.
The director, Sam Mendes, is new to action sequences on this scale, and in an effort to maintain the level of tension, he resorts to a lot of intercutting. While Bond battles it out in the field, MI6's technology enables M to observe and instruct. It's a ploy that serves the theme well, but I missed the intricacy of the stunts Martin Campbell came up with in Casino Royale, still the most satisfying of Craig's three 007 films. And there's some sloppy writing. The slinky Cambodian-French actor Berenice Marlohe is one of its casualties - her bit of the storyline is both perfunctory and nonsensical.
But Ralph Fiennes makes a highly promising start as MI6's new chief, and Ben Whishaw, - John Keats in Jane Campion's Bright Star - is a brilliant choice as the new Q - an urbane young nerd with attitude.
The future looks bright for the series, but Bond desperately needs to forget about his aching muscles and get back in touch with his libido.
Directed by Sam Mendes
Rated M, 143 minutes