On Halloween night 1964, a twenty-three-year-old Bob Dylan spellbound an adoring audience at Philharmonic Hall in New York. Relaxed and high-spirited, he sang seventeen songs, three of them with his guest Joan Baez, plus one encore. Many of the songs, although less than two years old, were so familiar that the crowd knew every word. Others were brand-new and baffling. Dylan played his heart out on these new compositions, as he did on the older ones, but only after a turn as the mischievous tease.

“This is called ‘A Sacrilegious Lullaby in, in D minor,’” he announced, before beginning one of the first public performances ever of “Gates of Eden.”

He was the cynosure of hip, when hipness still wore pressed slacks and light brown suede boots (as I remember he did that right). Yet hipness was transforming right onstage. Dylan had already moved on, well beyond the knowing New Yorkers in the hall, and he was singing about what he was finding. The show was in part a summation of past work and in part of summons to an explosion for which none of us, not even he, was fully prepared.

The times seemed increasingly out of joint during the weeks before the concert. The trauma of John F. Kennedy’s assassination less than a year earlier had barely abated. Over the summer, the disappearance in Mississippi of the young civil-rights workers James Chaney, Andrew Goodman, and Michael Schwerner, and the recovery of their beaten and murdered bodies, had created traumas anew. President Lyndon Johnson managed to push a civil-rights bill through Congress in July 1964; by early autumn, it seemed as if he would trounce the archconservative Barry Goldwater in the coming election and usher in an updated New Deal. But in August, Johnson received a congressional blank check to escalate American involvement in Vietnam conflict. On a single day in mid-October, the Soviet leader, Nikita Khrushchev, was overthrown and the Communist China exploded its first atomic bomb. A hopeful phrase of the decade was quickly winding down, and a scarier phase loomed.

Dylan’s style and his art were changing too, with an accelerating and bewildering swiftness befitting the times. As early as the summer of 1963, he had put the folk establishment on notice in “For Dave Glover,” a prose poem he was asked to write for the Newport Folk Festival program, asserting that, although he had great respect for the older folks songs and their traditions, he would write new songs as he liked, for himself and his friends. In January 1964, he complained in a letter to Broadside magazine about the pressures and guilt that had come with his growing fame. Out of the blue, a letter then appeared in Broadside from Johnny Cash, praising Dylan as “a Poet Troubadour,” and bidding the world to “SHUT UP! . . . AND LET HIM SING.” But the din around Dylan had barely begun. In late July, his performances at the Newport Folk Festival of new material, including “Chimes of Freedom,” followed, two weeks later, by the release of Another Side of Bob Dylan, badly shook the older folk-music establishment. In Sing Out! magazine, Irwin Silber published “An Open Letter to Bob Dylan,” complaining that Dylan’s “new songs seem to be all inner-directed now, inner probing, self-conscious—maybe even a little maudlin or a little cruel on occasion.” Noting, with a familiar left-wing combination of vagueness and menace, that he was not alone in his disquiet, Silber warned Dylan not to turn into “a different Bob Dylan than the one we knew.” (Dylan responded by instructing his manager, Albert Grossman, to inform Sing Out! that he would no longer send the magazine his songs for publication.)