Of course, as they readily acknowledge, ‘it is not enough merely to be prolific’. Shortly afterwards comes the inevitable bout of agonising over how far Winterbottom’s filmmaking can be understood as an expression of individual personality, given that he relies on a loyal group of collaborators, rarely takes a script credit, and shows little consistency in style or theme. They then set out to demonstrate their subject’s individuality by listing his many debts. One chapter looks at his cinematic influences, from Ingmar Bergman to Lindsay Anderson; another compares his adaptations of Thomas Hardy and Laurence Sterne to their literary counterparts; a third runs through a laundry list of genres he has tackled, from the western to the musical to science fiction.

Probably the strongest chapter is the one that considers Winterbottom as realist, a shaky concept that at least allows the authors to home in on a few of his persistent traits. As they point out, his characters are defined more by physical appearance than by psychologically detailed ‘back stories’, and are always shifting from one chaotic or menacing environment to another, with kinetic camerawork reinforcing the impression of a world in constant motion.

Though nearly all of Winterbottom’s protagonists are buffeted by impersonal forces, he treats locations as ‘places where people live, not the stuff of social statements’, as the authors suggest. His overt political stances are comparable to those of Amnesty International, and it would not be much of a stretch to position him alongside the more populist Danny Boyle and Guy Ritchie as representative of a Third Way in British cinema, outflanking both heritage conservatism and the old-school militancy of a Ken Loach.

Rightly or wrongly, McFarlane and Williams avoid drawing any such parallels (Tony Blair does not even rate a mention in the index). Instead, their usual procedure is to scour the bleak landscape of each Winterbottom film for a redemptive kernel of hope. Most often this means a warmth generated by a bond between two characters: the ‘kindly friendship’ struck up by two ordinary Londoners at the end of Wonderland (1999); the affectionate bickering of actors Steve Coogan and Rob Brydon in Tristram Shandy (2005); or even the amour fou of the murderous heroines of Butterfly Kiss (1995).

There is something mushy, if not outright evasive, about this all-you-need-is-love school of analysis, which accords all too well with the way that Winterbottom’s weaker films slide into platitude. The tedious In This World (2002), for instance, seems to have little content beyond a straightforward message of compassion for refugees, repeated until it loses all force. This is the real challenge which any defender of Winterbottom has to meet: is there a non-obvious level to his work, or even a secretly ‘high-flown’ artistic goal?

One answer is hinted at here in various passages that track the prevalence in Winterbottom’s films of characters who are ‘doubled’ or ‘split’. So, for instance, Coogan, in Tristram Shandy, plays the hero of Sterne’s novel and also ‘himself’ as the star of a film-within-the-film. The falsely accused teenagers whose plight inspired The Road to Guantánamo (2006) likewise appear as ‘themselves’ in interviews, besides being portrayed by actors who look nothing like their models. More subtly, the leads in the experimental 9 Songs (2004) serve, in effect, as their own body doubles, with hardcore sex scenes straddling the line between fiction and documentary.

All this suggests that Winterbottom’s brand of ‘realism’ is far from straightforward. The generally derided 9 Songs illustrates a further point that McFarlane and Williams never quite make directly: the close connection in his work between the real and the obscene, or the conventionally unshowable – a category that includes not just explicit sex but also the massacre footage in Welcome to Sarajevo (1997), the killing of a pig and the very bloody childbirth scene in Jude (1996), and the glimpse of a small boy’s threatened penis in Tristram Shandy.

Given that at least some of these examples are faked for the camera, it is probable that Winterbottom is less concerned with bearing witness to actuality than with jolting the viewer out of a complacent relation to the image. This is where he meets up with his own American double, the equally flexible Steven Soderbergh, whose last few films – Che (2008), The Girlfriend Experience (2009) and The Informant! (2009) – are all preoccupied with what psychoanalytic theorists might call ‘the disappearance of the human subject’.

Winterbottom’s version of this is to identify the distinction between persons and non-persons with the line separating authentic from false images. (If that sounds high-flown, think of what happens when a guard checks your passport.) Since authenticity can never be absolute, Winterbottom concentrates on figures that hover in a kind of limbo: refugees and terror suspects, celebrities wrapped up in their unreal star personae, lovers who appear as bodies and little more. The question of if and how these phantoms can acquire fully fledged subjectivity is ultimately a political one, though it is banished from the fictional narrative to re-emerge on a formal level in the instability of the visual field itself.

Perhaps this is what McFarlane and Williams mean when they describe Winterbottom as ‘a modern exemplar of the screen’s humanist tradition’. However, I am not convinced they have wholly succeeded in thinking through the relationship between surface flux and the ‘depth’ that supposedly guarantees value and meaning. Still, they have written a stimulating book that should encourage readers to ponder not just Winterbottom, but the broader question of how cinema can do justice to the world beyond the screen.