They’re going now. One by one, voices fading, old bones creaking, they’re slipping off-stage to the accompaniment of guitar strings and harmonicas, to be followed by the sounds of silence.

So long, Paul Simon, who sang in “I Am a Rock” of loneliness and alienation: “I have my books/And my poetry to protect me/I am shielded in my armor/Hiding in my room/Safe within my womb/I touch no one and no one touches me.”

When first heard, the language seemed weirdly out of place. Frankie Avalon never sang like that. The new stuff arrived in a pop music era when the big stars were boys with blond pompadours, and every song told a tale of high school rings and dancing at the hop. It was sugarcoated stuff in two-minute installments for teens whose attention spans were already showing signs of shrinking.

And suddenly in the ‘60s, there were these solitary men saying to the whole country: We can do better than this.

So long, Neil Diamond, who sang in “America,” a song that still resonates so loudly today: “Far/We’ve been traveling far/Without a home/But not without a star/Free, only want to be free/We huddle close/Hang on to a dream/On the boats and on the planes/They’re coming to America.”

Fabian never sang like this. But the new guys declared it was time for music to grow up, and they transformed bubble gum pop into anthems of war and politics, of race and religion, and emotional turmoil.

So long, Leonard Cohen, who urged us to accept our shortcomings in his “Anthem”: “Ring the bells that still can ring/Forget your perfect offering/There is a crack in everything/That’s how the light gets in.”

Cohen, 82, died in November of 2016. A few months ago, Neil Diamond, 77, announced he was retiring from touring after being diagnosed with Parkinson’s disease. A few weeks later, Paul Simon, 76, said he’d tour one last time and then lower the curtain, too.

And we haven’t even mentioned Bob Dylan yet. At the start of the new millennium, Andrew Motion, the British poet laureate, called Dylan one of the greatest artists of the century, noting “the dramatic sympathy between the words and the music; the range of his devotions; the power of self-renewal; his wit; his surrealism; the truth to experience.”

Dylan has announced nothing about leaving us. But he’s nearly 77, so he gets lumped in with the others — the great quartet of singer-songwriters, each of them with deep Jewish roots, who arrived roughly half a century ago and made American pop music finally cast off its juvenile simplicity.

Each helped give America a conscience. Their music was a kind of journalism, a challenge to take part in the struggle for equal rights or the anti-war movement during Vietnam, or the little dramas down in the shadows of a Baltimore hotel when Dylan wrote of the lonesome death of Hattie Carroll.

Or the lyrics took us on journeys to the dark recesses of our isolation, our sense of insecurity, of not being able to keep pace in a chaotic world.

When these four burst onto the scene, a whole generation stayed up late debating the meaning of their lyrics, and telling ourselves how much hipper, and more sensitive and insightful we were than our parents, who were still enjoying Lawrence Welk, or our older siblings who were still doing the box step to Paul Anka.

I don’t know why Jews have always had such an affinity for song, but it’s right there on the record: from Berlin to Kern and Gershwin to Rodgers and Hart, from Rodgers and Hammerstein to Sondheim, on through the rock era.

Maybe it has to do with yearning, with feeling slightly outside the heart of America, and wanting to come all the way inside and have our say, to feel part of the full national family.

It was our four troubadours who wrote songs the way few ever had, who told the whole country we could have a good time lifting our voices — and still tell a story worth hearing.

A former Baltimore Sun columnist and WJZ-TV commentator, Michael Olesker is the author of six books. His most recent, “Front Stoops in the Fifties: Baltimore Legends Come of Age,” has just been re-issued in paperback by the Johns Hopkins University Press.