Since January 2010, Carmen Callil, Justin Cartwright and I have been reading for the 2011 Man Booker International prize. Never heard of it? Well, it only began in 2005, so let me fill you in. The prize is awarded every two years to a living author, is worth £60,000, the winner is chosen solely at the discretion of the judging panel, there are no submissions from publishers and the judges consider a writer's body of work rather than a single novel.

This provides a beguilingly open-ended brief. It is up to us judges whom to read, what to read, and how to read, until one day a puff of smoke will go up (in Sydney on 18 May) and a great writer will be honoured. The three previous winners were Ismail Kadaré, Chinua Achebe, and Alice Munro.

It was hard to know where to start. We listed about 60 authors we thought should be considered. We consulted the list of novelists that our predecessors had discussed: some 80 names. We asked novelists, editors, academics, translators, publishers, critics and highly literate friends for their suggestions. We ended up, almost, with more than we could cope with. Not entirely undaunted, we have read and read and read some more, animated by the awful thought that we could be missing someone of the highest stature.

People often ask the annual Booker judges: "How many books did you read?" With the International prize there is no answer other than "thousands", for the prize honours a lifelong achievement in writing, and is tested by the judges' lifelong achievement in reading. But if you must: how many have I read since we began? The answer is 200-ish. And I've enjoyed almost every one, because if I didn't I just moved on to something better. We'd agreed to test to strength: no matter that some of a writer's output is of lesser quality, as long as the heights are majestic.

This process involves a different set of challenges from those involved in judging the annual Man Booker prize. When Martyn Goff, then administrator of that prize, invited me to be a judge for 2005, I asked him what a judge actually does? "It's simple," he said. "Just pick the best book." The International prize has a more ambiguous and elastic rubric. John Carey, chair in 2005, nicely observed that "the task allocated to us has been to size up the giants and arrange them in order of merit". Two years later, Elaine Showalter quoted this sentiment approvingly, while Jane Smiley, in 2009, observed that her "greatest wish is that the members of the next jury, for the 2011 award, will be overwhelmed with reading and endlessly frustrated by the requirement that they must choose one out of so many as 'the best'".

"Overwhelmed" is fair enough: by the sheer scale of it, by the responsibility it entails, and by the pleasure it has given me. But I am uncertain about this "best" business. Suppose, to avoid citing contemporary names, we were giving this award in 1923, and found ourselves arguing whether Marcel Proust was "the best", or James Joyce, or Thomas Hardy, or Joseph Conrad. That is an impossible, and unrewarding, question to pursue. Better to wonder which one of them we would wish, at that time, to honour with such a prize, and for what reason. Proust, known to be terribly ill as he works feverishly to finish his 12-volume magnum opus? The brilliant Joyce, Ulysses just recently published, at the peak of his powers? Hardy, in his final years, for a monumental lifetime achievement? Or perhaps Conrad, whose last novel was weak, but who had in one astonishing 14-year period produced masterpiece after masterpiece? I think that "most deserving of recognition" is a better criterion than "best", and its slipperiness is animating.

We tried to decide the list of finalists on literary merit alone, without questions of balance, or quotas, though this is an impossible goal. If we were (however improbably) to produce a list with no writers in translation, it would offend against the spirit of the prize; if only writers in translation, it would seem impossibly weighted against writers in English. Equally, one might be unhappy with a list without women, or men. But what of further criteria? Should we have a representative from each continent? What is to count as a substantial body of work? What are we to make of so-called "genre" fiction?

We agreed from the outset that much of the fun would lie in the arguments. This has sometimes been true and sometimes not. All of us have deeply held beliefs about excellence in fiction, and can defend them stoutly. I've been fortunate in my fellow judges, who are soaked in literature: at times it felt as if Carmen had published half of the books we were reading, and Justin had reviewed the other half. Our debates have been wide-ranging, sharp, and sometimes abrasive. You win some, you lose some. And every loss hurts, every cherished author who bites the dust an occasion for bitter regret. We have sometimes blamed ourselves for failure of persuasiveness, or each other for failure of discrimination. This has largely been civil, and always conducted over a monthly dinner that we took turns cooking in our own homes. If you lost an argument you could, at least, eat some more chicken and fill your glass. There would occasionally be a cessation of xxx's at the end of our emails, but they always came back.

It would be presumptuous and fatuous to comment here on "the state of world fiction". Very few readers in English are able to make such a judgment, for as former judge Alberto Manguel once pointed out, only 3% of the books published in England are translations (compared to 26% in Italy). We are significantly disenfranchised, to an extent so humiliating that it reminds me of the hapless contestants on those awful Japanese TV shows, being subjected to a litany of impossible tasks or questions. "Which Romanian novelist should one read? Who are the best Chinese writers of fiction? What's good coming out of north Africa?" Most literate readers in English would not know. And many, alas, would not care very much either.

I don't blame "them". I have often been similarly lazy and incurious. Anyway, it is hard to get reliable guidance on who is worth reading. And there is – no shirking this – the problem of translation. My generation of critics was raised to attend to the words on the page. That is what matters, that is what literature is (Jonathan Miller says somewhere that characters in literature "are sentences"). So are writers whom one encounters only in translation not significantly denatured when the words we read, however excellent, are not their own? (The prize acknowledges this by offering a further prize to the translator of the winner.).

There is much that needs be said about this, but not here. I have consoled myself with the thought that, after all, I have spent a lifetime revering Dostoevsky and Flaubert only in English, yet I love them every bit as much as Dickens or Joyce, even if I am reading them through a veil.

It sounds a trifle post-colonial to talk about authors one has "discovered", but I have gratefully made the acquaintance of many exciting writers from other cultures, whose work helps to contextualise our own literature, not always to its advantage. During a discussion of a much-loved contemporary writer in English, Carmen remarked that his work seemed "pale" in comparison to that of many writers from more stressed cultures, in which people lived at the endangered edge of things. She was right, though I wondered aloud if she found Jane Austen similarly pale? "Certainly not!" she said.

None of our chosen authors are "pale". What adjectives might apply? The judges' descriptions of their chosen authors include: magical, passionate, elegant, ebullient, startling, eloquent, powerful, spiky, enthralling, luscious, engrossing, puckish, fascinating, astonishing, extraordinary, perfect. A bit over the top? Certainly not. The best way to confirm this is to read extensively through our choices, which will provide many months of intense pleasure. I know, I've done it.

The 2011 list of finalists honours 13 great writers from around the world. It is, we think, diverse, fresh, and thought-provoking. We have focused entirely on quality of writing, and been delighted to ignore supposed genre categories, like "thriller" or "children's book" which might have excluded writers as important as le Carré and Pullman. By good fortune rather than design, our list has a reasonable ratio of men to women, writers in translation to writers in English, writers towards the close of a distinguished career to writers in the midst of one. We are delighted to "recognise" them, and it will be a damnable task choosing between them.

• This article was amended on 4 April 2011. In the original, the date for Sydney announcement of the International Man Booker prize was given as 29 May. This has been corrected.