Bob Dylan is the rare artist who, at 75, retains the power, energy, and restlessness that distinguished his early work. As both a recording and performing artist, his electricity is unabated, and he continues to make vibrant contributions to the post-folk culture he virtually created. That he has achieved this is astounding; for those of us who have followed his career and know something of its roots and evolution, it is not surprising. He constantly recasts his song catalogue, the depth of which by 1965 (let alone 2016) was unrivaled in the rock/folk/singer-songwriter genre he invented, to match his current sound, and commands a fluidity of vision in his writing that sees beyond the trees and perhaps the forest as well. Witness “High Water,” a tribute to Charley Patton (whose “High Water Everywhere” is a stone cold delta blues barking, howling, classic), from 2001’s Love and Theft. This is a blues about love and the water that rises, that has picked up some oldtime, some drone, shaking and breaking and name-checking muscle cars and evolutionary philosophers. The thing is that it works because when Dylan sings “the cuckoo is a pretty bird” that’s a kind of referenced code that he’s hollering back to Patton. He’s writing a blank check to freely associate (find and listen to a version of “The Cuckoo” and you’ll get what I mean), to make the rhyme work and throw meaning to the wind and to the listener. Harder than it sounds because it’s about the sound, what music is, what makes its power inexplicable. To make that warble on the 5th day of July, and trace your absurd and beautiful melody: it takes courage and a resolution that comes at a price only Dylan, and maybe Patton, knows.