Bob Dylan’s “Knockin’ on Heaven’s Door” has been covered by everyone from Avril Lavigne to the Grateful Dead — and, most famously, by Guns N’ Roses, who made it a hit in the early Nineties. Now, ...

The writer Michael Walker once theorized that the sixties — not the literal decade but the idea or more accurately the vibe — actually ended in 1973. The suggestion was that the era’s halcyon artists ...