Hearing Christopher Ricks speak about his early encounters with the Eng Lit canon, it seems almost inevitable that his career as a literary critic would see him, more than half a century later, the Warren professor of humanities at Boston and professor of poetry at Oxford, having held the King Edward VII professorship at Cambridge. How many other schoolboys would even have realised, let alone celebrated, their "terrific luck" that two English teachers, both liked and respected, disagreed profoundly as to whether Paradise Lost was any good? And how many others would have reached for Milton's epic as a strategy for dealing with the vicissitudes of school life?

"Like many people I sometimes had to protect myself at school, and I did it partly through snobbery," explains Ricks. "And that included thinking that I must be the only person at school who was reading Paradise Lost for pleasure. But it really was the most magnificent science fiction and much better than any of the comics I was reading." Of the teachers, one was a Cambridge Leavisite who deplored Milton's epic, the other a "more old-fashioned figure who said Paradise Lost was very good. And of course he was right. But the important thing is that from the age of about 14 I realised that people could have genuinely held and intellectually credible differences of opinion."

The idea that Milton was "very good" provided the subject of Ricks's first book and he has gone on to produce ground-breaking works on, among others, Keats, Tennyson, TS Eliot and Beckett. Ricks has been described as holding in his head all of English poetry, and to see him lecture is to see him repeatedly reach into this apparently infinite database for the most subtle and apposite comparisons, echoes and rebuttals. It is a dazzlingly impressive gift that will be on display next month in Oxford when he delivers the second of 15 lectures required over the five-year term of his poetry professorship.

WH Auden once described Ricks as "the kind of critic every poet dreams of finding", and fellow critic Frank Kermode describes him as "virtually unique in the profession. He has a wonderful memory, an extraordinary, and perhaps sometimes slightly overdeveloped, sensitivity to language, is amazingly industrious and is a very remarkable reader of verse. In his line he is the best in the business and his achievement in his edition of Tennyson is just about as good as you can get."

Ricks follows Paul Muldoon into the Oxford post and Seamus Heaney and James Fenton before him. Fenton has described the unusual process whereby candidates are directly elected by Oxford graduates as "eccentric, irrational", and the choice of a scholar rather than a practising poet this time was unpopular with some. With 214 votes, Ricks, who was widely seen as the establishment candidate with the support of nine heads of Oxford colleges among others, won by a comfortable margin. The votes for poets were divided between runner-up Peter Porter (175) and Anne Carson (105), who came third. Oxford academic and poet Craig Raine says ideally a poet should fill the post. "It is not an anti-Ricks point, because he will be very good. It's just that we have a lot of academics who lecture here and I thought you needed something special, and that is a writer. But 15 lectures is an awful lot of work; it is a book. So my idea was if a suitable poet wasn't available maybe it would be better to ask a distinguished writer from another field."

James Fenton, in the run-up to the election, also pointed out that the 15-lecture requirement "turns out to be rather an assignment (as Heaney and Muldoon will tell you), and it's not a bad idea to bear this in mind when you choose a can didate. It should certainly be someone with 15 things to say." Few people expect this to be a problem for Ricks, who will also deliver two Oliver Smithies lectures, on Henry James, in Oxford next month.

Ricks says he has always been in favour of academics being both general practitioners and specialists. "Milton, for instance, is too important to be left to Miltonists and he is also too important to be left to non-Miltonists. Students need lectures from someone who had devoted time to Milton and also discussion with a generalist who could become involved in those questions that Miltonists would simply not raise."

He has always taught subjects he has never had any intention of writing books about and was for many years also a productive literary journalist who took a view on pretty much anything his editors sent him. It was his early review of Heaney's 1965 debut, Death of a Naturalist , as his supporters for the Oxford post noted in their manifesto for him, that "helped to launch Heaney's career". His New York Review of Books review of Philip Larkin's The Whitsun Weddings (1964) was instrumental in winning Larkin a North American readership.

At Boston, Ricks teaches "most things from Shakespeare to Bob Dylan" and his most recent book, Dylan's Visions of Sin (2004), is a characteristically attentive reading of the songwriter's work. Reactions ranged from respect to incredulity. John Sutherland calls Ricks the best reader in the discipline but he sees the Dylan book as "a huge mismatch between method and subject. Dylan is bloody good, but he is not Shakespeare and Ricks goes wrong in applying to him this laser-sharp intensity of reading. No matter how much authority the critic has, we are in the territory of sow's ears and silk purses, but I do acknowledge that there is something magnificent about the enterprise."

Ricks brushes off the complaint. "I think Dylan is an astonishingly generous artist who is condescended to when people say it's very clever of me to find all these things in his work." Ricks's "cleverness" can irritate some readers but the critic and academic Martin Dodsworth, a university contemporary, says his weakness for puns is part of what makes him such a vivid and powerful critic. "He thinks through the power of a word and its place in society. He has written very well on 'prejudice' in the Eliot book and has written very interestingly about lying. He is not just interested in literature, but also in the way words do things in the world."

Russell Davies picked up on the trait when reviewing, in verse, a Larkin Festschrift , which included a piece by Ricks. Davies's poem-review was set at a noisy party where Larkin was going round talking to everyone who had contributed:

   Now poet must holler to poet; and Larkin must mime his hellos -
   To the utter enchantment of Christopher Ricks
   Who loves, above all things, the way meanings mix.
   "Did Larkin mean 'Hell-o' or 'Hull-o'?" (He licks
   His lips, as an essay grows.)

Ricks was born in Beckenham, Kent, in 1933. His French mother, Gabrielle Roszak, came from a family of furriers. His father, James Ricks, worked in the family firm making overcoats. "The firm proudly boasted that their coats would last a lifetime," says Ricks. "But after the war women didn't want coats that lasted a lifetime. They wanted, with a clear conscience, to jettison clothes when the fashion changed. My father had run the business by getting to work quite late, doing the Times crossword and then having a working lunch." He says the firm never really caught up with the changed world and eventually went bankrupt.

His parents divorced when Ricks was three. His older brother Donald "was sort of allocated to my father and I was sort of allocated to my mother". But both boys were sent to board at King Alfred's, a direct grant school in Wantage where Ricks ended up as head boy. An unlikely near contemporary was Lester Piggott, whom Ricks remembers as "a terrible, tiny bully".

The academic and Keats scholar John Barnard was also at the school and took over from Ricks on the left wing of the school hockey team. "I'm three years younger than Christopher and remember him as a kind of mythic figure. He was clearly much cleverer than most people and the rumour was that he did the Times crossword before the headmaster. He was also the only person in school with a golf club and he would bash a golf ball round the sports field, which was a very powerful and unworldly thing to do." Ricks smiles and says he gave up golf "when the Conservative party invaded Suez. It might not seem much of a gesture, but it mattered to me and I think it sent a pretty clear signal."

King Alfred's had Oxford connections, such as the headmaster Cyril Bailey, who was taught to ice skate by Matthew Arnold, and wrote the definitive translation of Lucretius - "for which he was mocked by Housman". Ricks duly won a scholarship to Oxford and, after two years' national service in Egypt as a 2nd Lieutenant in the Green Howards, became the first member of his family to go to university.

"The army was a bit of a nightmare," he says. "I didn't see any of Egypt because I was behind wire guarding rotting potatoes with killer dogs. And I loathed the anti-Arab prejudices of many in the army although the only Arab I actually saw was a man who electrocuted himself and was killed while doing the ironing."

Ricks went up to Balliol College in 1953 to read English, and still delights in stories about eccentric Oxford figures, such as a mean tutor who sat so close to his meagre fire "that every now and then there would be a smell of burning tweed and he would have to put himself out". He is still impressed by people who are called names that seem to have no relation to their initials. "CS Lewis was Jack. Wonderful."

He remembers himself as being a "morbidly conscientious" student whose, ultimately unfulfilled, ambition was to be editor of Isis, although he did make it to literary editor. John Gross was a fellow undergraduate and remembers his initial impression of Ricks as being "a bit abrupt, a little pedantic. He was still very much the man who had been an officer in National Service and he always seemed to know what he wanted in a way that very few others did. But when you got to know him he was brilliant and very funny and in no time at all he established a little group of friends and admirers to whom he used to give tea in his rooms."

Ricks was duly awarded a first and in 1956 embarked on a BLitt in 18th-century heroic couplet poetry. He praises the BLitt system, as opposed to working for a PhD, "because it cuts free of that 'making an original contribution to knowledge' business. I think that is much too much to ask of someone in their mid-20s and it explains the paralysis in doctoral work. The amount of research you have to do to find out that no one has done what you have done is quite different from an apprenticeship in sources, authorities, and methods. Of course, if the apprentice comes up with an original piece of leatherwork or glassware that's good. But it is an apprenticeship."

The same year he began his BLitt he married Kirsten Jensen. The marriage, which produced two sons and a two daughters, broke up acrimoniously in the 1970s and in 1977 Ricks married the American photographer Judith Aronson. They have two daughters and a son and live in Boston and in an isolated Gloucestershire cottage that Ricks has owned for 45 years.

Ricks became a research fellow at Bal liol in 1957 and the following year a fellow of Worcester College, Oxford. By this time Barnard was an undergraduate, being taught by his former head boy. "As a young lecturer he certainly wowed the undergraduates," recalls Barnard. "He is astonishingly good at analysing how sentences work, how words and allusions work, and would hold small meetings in his house where we would very carefully go through a poem looking at the syntax, then the double meanings in the words and then the rhymes. It wasn't quite as strict a sequence as that and the meetings were completely informal and he assumed a kind of equality which was remarkable."

He taught at Oxford for 11 years until 1968 and says he generally enjoyed, and still enjoys, teaching. "But I ceased to enjoy it at the rate of about 3% a year. So after 10 years at Worcester I had lost interest in the lowest 30% of the class. The problem was that their way of being boring was the same way of being boring I had experienced every year before."

Milton's Grand Style (1963), his first book, followed up his long-standing interest in the differing critical responses to the verse. "I like dealing with things that genuinely puzzle me and it was a genuine puzzle that Leavis and Eliot, both of whom I admire and who usually disagreed about so much else, should so strangely agree about how bad Milton was when he is obviously extremely good. I needed to work it out for myself."

"Milton's Grand Style made me into a Miltonist and as a result I ended up doing a doctorate on Milton," says Archie Burnett, professor of English and co-director with Ricks of the Editorial Institute at Boston University. "His attention to syntactic detail, his close inspection of the way the poem moves from line to line and the subtleties and ambiguities in it were a revelation to the Milton community. It was a conclusive answer to those who had alleged that Milton's poetry had sacrificed expressiveness for a superficial impressiveness."

Throughout his time at Oxford, Ricks was combining academic work with literary reviews. He had first contributed to the Spectator as an undergraduate - "I was CB Ricks which I thought was along the same lines as TS Eliot" - and continued despite the sense in some Oxford quarters that it was somehow infra dig. Barnard recalls him "picking up on Beckett and Lowell very early and saying what was good about them. I remember him walking past my desk and giving me a copy of the first Geoffrey Hill. He seemed to be at the cutting edge."

Karl Miller, Ricks's editor at the New Statesman in the 1960s, says that "what he wrote in these journalistic pieces was substantially the same as what he would write in a book. Sometimes reviews are lesser things than books, but books can also be lesser things than reviews." Ricks credits Miller with having spotted the Heaney book and sending it to him for review - "but I'm glad I said how good it is" - and says he is proud of early reviews of Hill and Larkin. "And I'm proud of a review of Norman Mailer's Executioner's Song . I think Mailer is a smash of a writer."

Miller recalls Ricks as being "one of the cleverest people doing that sort of thing and he had his own way of doing it. He was sharp and argumentative and a defender of principle while also being rather ludic and playful. He was also very combative and if you hold combative views as a writer there can be pressure on you to inflict pain and unfairness on people, but he managed to avoid that."

That said, one review did prompt TS Eliot to bring in the lawyers when Ricks said Eliot's clearing Wyndham Lewis of having fascist sympathies was like the pot calling the kettle white. "I was right and wrong to make the joke, which was quite a good joke," says Ricks. "If you follow it remorselessly it suggests Eliot was a fascist which I don't think he was. But he also wasn't in a position to clear other people of the accusation. There is too much that Eliot is associated with that is not without its links to fascism. But Sue, Grabbit and Runne sent their letter and there was some form of apology."

Eliot remains in Ricks's pantheon of great writers. "I read and re-read him and think him an astonishing poet and critic and phenomenon. I can't see that England in 1910 deserved him. When Mrs Eliot asked me to look at her husband's unpublished poems in a notebook [which he later edited as the 1996 Inventions of the March Hare: Poems 1909-1917 ] I did not quite swoon, but ..."

Ricks left Oxford in 1968 to become professor of English at Bristol. There he worked on Keats and Embarrassment (1974), in which he made the then revelatory connection between the letters and the poetry. It was also at Bristol that he first published his, still definitive, edition of Tennyson's poetry. "I loved doing the Tennyson and am very pleased it exists," he says. "When I was in my mid-20s someone once said to me at a party that I was 'brilliant but unsound'. I thought I should do something about that and the way to show you are sound is to edit things."

In 1975 he moved to Cambridge and was later appointed King Edward VII professor of English literature. Almost three decades later Ricks remains animated about constitutional and administrative scraps in which he became embroiled at the university. One became known as the "MacCabe Affair" when a young don, Colin MacCabe, was denied tenure. It seemed to crystallise the theory wars, in which new ideas - represented by MacCabe - were being thwarted by the fuddy-duddy Cambridge establishment. The dispute was also seen as an epic battle between Ricks, cast as a defender of the traditional approach to the study of literature, and the more theory-friendly Kermode.

"The war of the scholars thing was overdone," says Kermode. "We were on different sides but there never was a serious confrontation between us. We were good friends and are still on excellent terms and I was very glad to see Christopher come to Cambridge. But he is not always an easy man to agree with. He is a very emotional man and if he adopts a cause he puts his personality into it. He has been very opposed to the whole trend in the last generation towards literary theory."

Both men agree the "heat and steam" has now largely gone out of the theory wars. "It does seem," says Ricks, "that a lot of people who were looking for a certain sort of salvation from literary theory - political and perhaps personal salvation - have been a little bit disappointed. There have been quite a lot of defections from the theory ranks and a lot of people have found out, to their mild surprise, that they were really liberal humanists all along. One shouldn't be complacent that fashions are sure to disappear without doing much harm. But it does seem to me that a great deal of good sense has prevailed and almost everyone now teaches, at least at undergraduate level, in a rather valuably old-fashioned way."

He also says that while there were personal and political elements of the "dissensions in Cambridge", there were also important constitutional dimensions. "Being a professor at Cambridge was a bit like being in the House of Lords. It was meant to be grand and important, but is in fact terrifically unimportant. Except by showing off, you cannot retain an audience. Why should people go to lectures at all if it doesn't affect their mark or their standing with the people who write references for them?" He says he hadn't supposed he could arrive at Cambridge and make a difference to the place, "but I had not imagined that which I knew. You can know perfectly well that the person you are about to marry is unpunctual, but not quite imagine what that will mean." So involved was he in administrative matters that it took some time for him to realise he was getting very little done "of what is called my 'own work'. I love that as an idiom because it assumes being paid to teach people is not your own work."

By contrast, since his move to Boston University in 1986, he has published a dozen new books. John L Silber was president of the university when Ricks was recruited and describes him as "one of the really dynamic centres of intellectual activity at BU. He sees around the corners of everything and sees the double and triple entendres whether they are there or not. Students respond to him in a way that is very rare. He is both respected and adored by the students."

At Boston, Ricks has edited The New Oxford Book of Victorian Verse (1987), a volume of Housman (1988) and Inventions of the March Hare (1996). There has also been Eliot and Prejudice (1988) and in 1993, Beckett's Dying Words. "The Beckett was another puzzle," he says, "given that Beckett thinks there is a great deal to be said for death and much less said for life. Beckett praises Joyce by saying the lan guage is so alive. But if you believe it is better to be dead, and better still never to have been born, how are you going to get good deadness into your language?"

The rows over the role of theory in teaching English followed Ricks to Boston and he eventually left the English faculty and now operates independent of any department as professor of humanities and as co-director of the Editorial Institute, a post-graduate centre for textual scholarship. In 2003, he was awarded the $1.5 million Mellon Foundation Distinguished Achievement Award. He will devote the money to work at the institute and, perhaps predictably, describes it as "a particularly sweet slice of the Mellon".

As for his "own work", he says that until recently he had files "bursting with what I hoped to mount into arguments and I had four or five things I wanted to write. Then they all got done and I felt slightly mortal but at the same time I was quite pleased. And then this wonderful Oxford thing comes up." The heading for his first three lectures is "Many Voices", a typically many-layered title; the phrase "is in Tennyson which goes to Eliot and then to Hill". The first lecture was about translations of French poetry into English and the second, called "From the Regional", will look at dialect poetry. "There are some lectures that could just as easily be read as listened to. But with these I think I wanted to do something explicitly lecturely." He will use recordings of readings of Burns and the 18th-century Dorset poet William Barnes, and in the third lecture, on song, recordings of Campion's settings of Tennyson. "And as I revere Dylan so much I will have to say something about him as well."

With Dylan's memoirs, Chronicles (2004), coming so soon after his own book, Ricks decided not to write about them, but can't resist commenting that an initial reading reveals that Dylan's "transitions from sentence to sentence and within sentences are particularly good and very continuous to what he loves doing in the songs." He doesn't hesitate to include Dylan in his personal pantheon alongside Empson, Eliot, Beckett, Larkin, Lowell and Hill. "I felt it was an extraordinary bit of luck to be alive at the same time as these great creators. I've had great pleasure from lots of dead poets as well, but I can't imagine not chafing to get hold of a new something by, say, Beckett in the week it came out."

Among contemporary figures, he cites Marcia Karp, Constantine Contogenis, Greg Delanty and Saskia Hamilton as "true poets". But it is to his pantheon, and to Empson, to which he turns when explaining why he so loves and values literature and why he has devoted his career to studying and teaching it. "Empson said one of the reasons we have arts and literature is that it gives us sympathetic access to systems of belief that are not our own. Some terrible recent developments seem to value solely in a work of art those things that corroborate what you already think. It assumes that the end of politics is establishing that your position is the only one for which anything can be said. But the thing that Empson most valued in the arts was that it allowed him to realise that intelligent, sensitive, compassionate and very good people could disagree with him. It is only through works of art, or people you are very fond of, that you learn this."

Christopher Bruce Ricks

Born: September 18 1933, Beckenham, Kent.

Educated: King Alfred's, Wantage; 1953-56 Balliol College, Oxford.

Marriage: 1956 Kirsten Jensen, two sons, two daughters, divorced; '77 Judith Aronson, one son, two daughters.

Career: 1952 2nd Lieutenant, Green Howards; '57 Andrew Bradley Junior Research Fellow, Balliol; '58-68 fellow, Worcester College; '68-75 prof English, Bristol; '75-86 prof English and King Edward VII prof of English; '86- prof English, Boston; '99- co-director, Boston Editorial Institute.

Books: 1963 Milton's Grand Style; '69 The Poems of Tennyson (ed); '74 Keats and Embarrassment; '84 The Force of Poetry; '87 The New Oxford Book of Victorian Verse (ed); '88 AE Housman (ed); '88 TS Eliot and Prejudice; '93 Beckett's Dying Words; '96 Essays in Appreciation, '96 Inventions of the March Hare: Poems 1909-1917 by TS Eliot (ed); 2002 Reviewery, Allusion to the Poets; 2004 Dylan's Vision of Sin.

· The second Professor of Poetry lecture, "Many Voices: From the Regional", will be given at the Examination Schools, High Street, Oxford, 5pm, February 21. Dylan's Visions of Sin is published by Penguin.