We had not planned to be in Afghanistan for the 1973 coup. In fact we had not planned much of anything. But that’s the way it turned out. When the Afghan king, Mohammad Zahir Shah, was ousted after a 40-year reign, we were in Kandahar in the courtyard of some hotel trying to learn how to ignore the flies. Another guest, who’d mastered the fly trick and attained imperturbability, had a short-wave radio. It picked up the BBC World Service news.

A coup? My two friends and I were on the hippie trail. This was not part of the deal, dude. Even Afghans seemed blown away. They of course had no idea that the overthrow of their monarch would presage decades of unrest in which the Soviet Union would find its quagmire and the United States discover the dangers of a short attention span.

They knew nothing of how the mujahedeen “holy warriors,” schooled in American-backed Wahhabi fundamentalism, would battle Soviet troops until they withdrew to an enfeebled Communist empire, how the Wahhabis would turn on their negligent American patron, how the Taliban would emerge to restore order, or how the United States after 9/11 would fight a long Afghan war with a disastrous Iraqi sidebar.

Nor did we. Afghanistan, even kingless, had majesty. Its coup seemed uneventful. We drove up to Kabul. I think we saw one tank.

The road to Afghanistan from London had led across a Turkey still impenetrable, where only the children smiled, the shah’s Iran, where Mashhad’s cobalt blue mosque made an indelible impression, and the dusty border near Herat, where we first became acquainted with the pride of the Afghan gaze.

Our VW Kombi was called Pigpen, named after the keyboardist of the Grateful Dead who’d died that year. The Dead loomed large, our sunshine daydream. “Truckin”’ was our anthem — until the cassette machine got stolen. Then we strained for the harmonies of “Uncle John’s Band.” In Kabul we had an Ace of Hearts painted on the front of Pigpen.

Up to Bamiyan we went and sat on the heads of the 1,500-year-old Buddhas, since destroyed by the Taliban as “gods of the infidels.” We gazed at the sacred valley. The peace seemed eternal; it would not be. Everything passes except the dream that it will not. In Band-e-Amir, the night sky was of a breathtaking brilliance. On my 18th birthday, I thought I found my star, blotted out the rest, and recalled the line from “Box of Rain” — “Maybe you’ll find direction around some corner where it’s been waiting to meet you.” Later, deep in the Hindu Kush, Pigpen broke down. Like so many before us, we limped out of Afghanistan but we brought the Kombi home. There is much to be said for journeys without maps.

So of course I had to resume the journey earlier this month at Soldier Field in Chicago, where the Grateful Dead sans Jerry Garcia regrouped on their 50th anniversary to bid farewell. I’d last seen them on a Haight-Ashbury pilgrimage in San Francisco in 1974. Well, we’d all changed. Peace signs had not won the day any more than time’s imprint could be effaced. A cynic would take the view that the dollar sign had prevailed. But the magic of the music, in its moments of improvised brilliance, precluded any such heartless reflection. Hugs and hopes of old and young filled the stadium. Phil Lesh, Bob Weir, Bill Kreutzmann and Mickey Hart still did their thing. Listen to “Friend of the Devil” and find yourself back on the road from Herat to Kandahar — four decades, a mere ripple on water.

A Palestinian friend and physician, Sahar Halabi, attended the concert with me. Her odyssey had taken her from Algiers to Liverpool and on to the Midwest. Later, she sent me something she had once written about her search for her family’s home, from which they were ousted in 1948 during Israel’s War of Independence, which Palestinians call their “Nakba,” or catastrophe.

She wrote: “The story of the old large house was a constant in my childhood, not because of the repetition, but because it was a palpable entity which I could almost touch with my imagination. To all of the Palestinian refugees in diaspora, the land of Palestine is not a physical place, only sheer longing.” On a visit to Israel in 2009, she goes back to the place where the house once stood and digs: “The old design of the intertwined blue and red curved lines of the tiles appear, and I understood. These were the tiles of the floors on which my mother took her first unsteady steps.” A fragment is now in her Chicago home.

Fragments, memories, conflicts, the intractability of understanding and the constancy of the Dead: What a long, strange trip it’s been. As Hart said, “I’ll leave you with this: Please, be kind.”