Judging by the weight of votes cast, the books of the century are a rather familiar lot: Ulysses, 1984, Proust's A La Recherche du Temps Perdu, DH Lawrence, Kafka and Hemingway feature largely. Simultaneously, it is possible to detect a certain amount of confusion over the evaluative techniques on display.
Most obviously, writers of the Joyce and Lawrence school are always acclaimed (mostly by other writers) for their "influence". And yet how truly influential is a novel like Ulysses? Its stream-of-consciousness narrative techniques may have enraptured a forgotten tribe of Sixties experimental writers, but it seems fair to say that its effect on the wider literary consciousness is more or less negligible.
An engaging take on the whole dilemma of "influence" turned up earlier this year, with the publication of Martin Seymour-Smith's compendious and ambitiously framed The 100 Most Influential Books Ever Written. Seymour- Smith, who died shortly after finishing the book, had no doubt where "influence" resided. The 20 or so 20th-century selections - in a list that takes in the I Ching, the Old Testament, Burke and Hegel - included Freud, Jung, Sartre and Chomsky.
The compiler's defence of this unashamedly egghead stance was that such books worked through an endless process of diffusion, trickling down from lecture hall to the broadsheet press and thence into the minds of the mass audience. The average tabloid reader won't have read Freud, the Seymour- Smith argument runs, but like it or not he or she lives in Freud's century.
At the same time Seymour-Smith includes no popular imaginative literature at all: female readers who responded to the character of Scarlett O'Hara in Gone With The Wind, he maintains, are merely responding to a stereotype.
Undoubtedly there is something in this idea of cultural hand-me-down that stealthily disperses and popularises highbrow, or even relatively highbrow, thought: one can see it at work through great areas of 20th- century English literature. It's possible to argue, for example, that Kingsley Amis's Lucky Jim (1954) almost single-handedly created what we now know as British literary slapstick, in which men behave badly, get drunk and make idiots of themselves with women.
At the same time, the "influence" of books of this kind, whether by Sigmund Freud or Kingsley Amis, is by its nature indirect. No survey of "influential literature", as far as I know, has ever concentrated on the substantial pile of books that have exerted a direct, practical influence on the way ordinary people live.
You are a British citizen in your sixties, let us say, born between 1930 and 1940. What are the books published in this century that will have categorically influenced your life? The most obvious one, perhaps, is the bound version of the Beveridge Report in which the whole basis of post-war social planning took root and grew. If official reports do not count, what about the substantial debt we all owe to the infantry training manuals issued to Allied troops in the Second World War?
Again, it can be argued that these aren't tangible influences. In that case, what about the profound influence exerted in the pre- and post-war era by fashionable childcare manuals? The obvious name to mention here is Dr Spock, but there must be hundreds of thousands of fifty- and sixtysomethings who were brought up on the teachings of his predecessor, Truby King. Rigid, four-hour gaps between feeds, plenty of fresh air and no cosseting - my mother was a Truby King baby and still remembers it. It could be argued that the now-forgotten Dr King helped to shape a whole generation's emotional outlook.
Then there are libraries full of "popular literature" with the capacity to alter, or at any rate to refine, the view that people take of the world. Joseph McAleer's recent history of Mills & Boon, Passion's Fortune, has demonstrated the enduring social effect of the popular romance. The same point could be made of the rows of boys' school stories that hammered home lessons about "playing the game" to generations of grammar school pupils.
If literary influence works from the top down, then it can sometimes operate from the bottom up. In terms of affecting the way in which ordinary people live their lives, then the Manual of Military Law has the edge over Ulysses any day.