Most pop music inhabits a permanent present; by its nature, the medium is disposable and transitory. One of Bob Dylan’s claims to greatness – made not by him but by many others – is that his enormous output of songs and recordings has a permanence and achievement far superior to those of other ‘popular’ artists. Its literary qualities have been scrutinized and lauded by eminent academics such as Christopher Ricks. But the deeply historical nature of Dylan’s output has, until now, received little attention. The American music critic Griel Marcus broached the subject in his book Invisible Republic, in which he outlined the young Dylan’s debt to a compilation published in the 1950s by the avant-garde film-maker Harry Smith, the Anthology of American Folk Music, of songs recorded in the 1930s. According to Marcus, it documented the ‘old, weird America’ of Appalachian ‘death ballads’, early blues, archaic Cajun love songs and strange nursery rhymes, such as ‘Froggy Goes a-Courtin’. Its influence was apparent in The Basement Tapes, the series of extraordinary recordings Dylan made in 1966-67 when he turned his back on the psychedelic silliness of that period to delve deep into America’s past and emerged again during the 1980s when he returned to many of the songs that inspired him as a young man in the two albums, critically maligned at the time, World Gone Wrong and Good as I’ve Been to You. Now Dylan has become the object of study by one of America’s pre-eminent historians, Sean Wilentz of Princeton University. Wilentz is interviewed in The Chronicle of Higher Education. His book is also reviewed favourably by Bryan Appleyard in The Sunday Times.