James Mangold’s film about Bob Dylan functions on the principle that guides the more memorable biopics of well-known personalities: “can’t know, don’t want to know”. A Complete Unknown takes its title from Dylan’s 1965 song Like A Rolling Stone. Dylan’s profound lyrics, which made him a cultural touchstone and won him the Nobel Prize for Literature in 2016, provide the most pointed clues to his enduring enigma.

The Oscar-nominated movie, which is out in cinemas, is based on Elijah Wald’s 2015 book Dylan Goes Electric! Newport, Seeger, Dylan, and the Night That Split the Sixties. The screenplay by Mangold and Jay Cocks uses Dylan’s transition from acoustic to electrical guitar as a framing device for a riff on musical traditions, celebrity and the cult of genius.

Dylan’s technical shift takes place over four momentous years. Dylan (Timothee Chalamet) arrives in New York City in 1961. While his background is hazy, there is no doubt about how fully formed he already is.

While visiting his ailing hero Woody Guthrie (Scoot McNairy), Dylan runs into renowned folk singer Pete Seeger (Edward Norton). Seeger and his wife Toshi (Eriko Hatsune) watch over Dylan’s steady progress as might fond parents. Dylan’s popularity revitalises American folk music, making him a top draw at the Newport Folk Festival, but...