For the past 20 years, former Aucklander Richard Thomas has been a professor of Greek and Latin at Harvard University in Massachusetts. He has written learned articles on Callimachus, Menander, Theocritus, Homer, Ovid, Horace, Propertius and Catullus. He is regarded as one of the world's leading authorities on the works of Publius Vergilius Maro (70-19BC), the Roman poet commonly known as Virgil.

Since the mid-1960s, Thomas has also been a devoted fan of Bob Dylan. In recent years he has presented lectures and seminars on His Bobness as well as dissertations on Virgil's Georgics, Eclogues and Aeneid. He is confident that Dylan's songs will survive their historical moment and continue to interest future generations. A classic in the making, you might say.

"Staff at Harvard are asked to give freshman seminars that can be outside the standard curriculum," Thomas explains. "It was largely in a spirit of fun that I first decided to do Dylan. But increasingly I've come to see that his songs are a legitimate field of study. They contain a kind of poetry that doesn't die because human nature doesn't change."

What exactly do the professor and his students talk about in the Dylan seminars?

"The approach is roughly chronological. We look at the way Dylan's career has developed since the early 1960s, his creation of various personae and his involvement in such genres as folk, protest and rock. We look at his appearances on film, too."

The 2003 movie Masked and Anonymous, which Dylan not only starred in, but co-wrote with director Larry Charles, was generally panned by reviewers. Todd McCarthy referred to it in Variety as "a mess", "a botch" and a clueless "three-ring circus". Roger Ebert described it in the Chicago Sun-Times as "a vanity production beyond all reason" with "the enormous cast wandering bewildered through shapeless scenes".

Thomas thinks they got it wrong. "Masked and Anonymous is a brilliant film - essential viewing for anyone interested in Dylan. I get my freshman students to watch it."

He thinks the allegations that Dylan "plagiarised" parts of his 2001 album Love and Theft from Junichi Saga's book Confessions of a Yakuza are fundamentally wrong-headed too.

"Dylan has always been an artist willing to adapt material from other sources, beginning with Woody Guthrie and other folk singers and bluesmen in his earliest songs. Often he acknowledges the debt, as he does with Hitchcock's Psycho in the 1964 song `Motorpsycho Nightmare' and Henry King western The Gunfighter, starring Gregory Peck, in `Brownsville Girl' from 1986."

Virgil was similarly willing to adapt earlier material, Thomas points out. The Aeneid draws extensively on Homer's account of the Trojan War in The Iliad. Virgil was also considerably indebted to other Greek writers of antiquity, such as Sophocles and Callimachus.

No writing comes out of a void. Authors have always influenced one another. Happily for Thomas, there is even a moment in a Dylan song -the 12-bar blues "Lonesome Day Blues" from Love and Theft - when the old growler starts quoting The Aeneid: "I am goin' to teach peace to the conquered. I'm gonna tame the proud."

Is Dylan a reader of Virgil then? Quite possibly. Thomas believes that Dylan's recent output shows an increasing awareness of classical literature.

"He was in Rome at the time of the September 2001 terrorist attacks. He's certainly aware of the parallels between Rome as an imperial power and modern America."

In 2005, Thomas gave a lecture called The Streets of Rome: The Classical Dylan at a conference on "Dylan's performance artistry" at the Universite de Caen in France. He repeated it at Auckland University this month. It is also one of the chapters in a forthcoming compendium of Dylan scholarship that Thomas has co-edited with Catharine Mason, associate professor of English at Caen.

While he enjoys making connections between Dylan and the classical world, Thomas is not about to get too carried away and begin translating "Like a Rolling Stone" into Latin. He has a sense of humour - and a sense of perspective. He's well aware, for example, that "Lonesome Day Blues" derives more from Georgia bluesman Blind Willie McTell (1901-59) than it does from Virgil.

Born in London in 1950, Thomas moved to New Zealand with his family as a small boy. He first showed a flair for Greek and Latin as a pupil at King's College, Auckland, in the mid-1960s. It was there that he began listening to Dylan too.

"Dylan's nine years older than I am. Although I'd love to claim that I was one of the people who snapped up his first album when it came out in 1962, in fact it wasn't until two or three years later that I became a fan. I wasn't all that single-minded about it. I listened to all the other music of the 60s too. I liked Neil Young. I went to the Rolling Stones concert at Western Springs."

In the late 1960s, Thomas studied law at Auckland University as well as Greek and Latin, but his love of classical literature gradually predominated. After completing his MA at Auckland in 1974, he embarked on a doctorate at the University of Michigan. He has lived and worked in the US ever since, but family ties have brought him back to Auckland at least once or twice a decade.

His admiration for Dylan has been one of the other constants in his life.

"What fascinates me about him is how he continues to change and develop. Sure, there are peaks and troughs in his career, but nobody else in pop or rock can match the quality of his output over such a long period. And he's still performing with remarkable frequency and intensity. It's possible to catch him in concert quite often. I saw him twice last year.

"No two shows are the same. Unlike most musicians of his age, he keeps experimenting, giving fresh interpretations to songs he has been performing for decades. Because his material is seldom all that specific in its temporal and geographical references, it travels and ages well. He still does `Masters of War' fairly frequently in concert, although it was written in 1962. It works as well in the era of Donald Rumsfeld and Robert Gates as it did in the time of Robert McNamara."

Thomas is not the only prominent academic who is mad on Dylan. Long-time devotee Christopher Ricks, professor of poetry at Oxford University, celebrated his 70th birthday in 2003 by publishing a 500-page tome called Dylan's Visions of Sin. Recent volume Do You Mr Jones?: Bob Dylan with the Poets and Professors (Pimlico, $35), is edited by Neil Corcoran, head of the School of English at the University of St Andrew's, with contributions from Aidan Day (professor of British literature and culture at the University of Aarhus, Denmark), Daniel Karlin (professor of English at University College London), and Sean Wilentz (director of the programme in American Studies at Princeton University).

What does Dylan himself make of all this scholarly attention? His own university career was very brief. He dropped out of the University of Minnesota after his first year, during which time he attended very few lectures and mainly hung out in Minneapolis folk clubs. After being presented with an honorary degree from Princeton in 1970, he wrote a cheekily satirical song about the experience, "Day of the Locust". Indeed, his general attitude to academia has always been scathing.

"His office has been very helpful in providing background information for my seminar course," says Thomas, "but there was no response when I invited him to attend one of the classes - and I didn't expect any."

With a wry smile, Thomas then quotes some lines from the song "Nettie Moore" on Dylan's latest album Modern Times: "Well, the world of research has gone berserk / Too much paperwork."