Syd Barrett is dead, and with him goes a substantial slab of rock history. The reclusive former member of Pink Floyd was the Salinger of music, a flaming creature who burned brightly at the center of '60s rock, who burnt out and lived out his years in the basement of his mother's house in Cambridge. But from Bowie to Blur, Barrett has remained the criterion, the benchmark by which much is measured. In his Guardian obituary, Nick Kent wrote that Barrett "will go down in history as one of the most uniquely inspired creative talents to have sprung up from the pop revolution." But Barrett's inspiration extends further than music.

The timing of Barrett's death seems even more melancholy, as his spirit imbues Tom Stoppard's new play, Rock-n-Roll (now playing in London's West End), which charts the fall and rise of Czechoslovakia between Dubček's Prague Spring and Havel's Velvet Revolution through the rock music of the age. The character of Barrett even makes a brief appearance at the top of the play as a Pan-like flutist — a Piper at the Gates of Dawn.

As this is Stoppard, Rock-n-Roll is a vast landscape of themes. Rock and recent Czech history serve as ballast for bracing discussions on Western culture and popular culture (the two terms seem interchangeable now), Marxism and philosophy (particularly the mind/body problem). It's a bold piece that at heart is concerned with the ability to retain one's integrity in the face of societal pressures.

Rock-n-Roll ranges from Cambridge to Prague between the years 1968 (that annus terribilis for Czechs) and 1990. Jan (Rufus Sewell), a young Czech student studying at Cambridge, is readying to leave England for the tank-filled streets of Prague, feeling it necessary to share his city's plight. He comes to say goodbye to his professor and mentor, Max (Brian Cox), a staunch Marxist who disapproves of Jan's motives for returning. "Sovereignty was never the point," Max says heatedly. "At the first flutter of a Czech flag, you cut and run like an old woman still in love with Masaryk."

The only thing Jan brings back to Czechoslovakia with him is an impressive collection of rock records that the re-emboldened communist authorities immediately impound. What follows is Jan's awakening to the deadening grip the Soviets have upon his city and country. He's at first encouraged by the lack of retribution from the commissars: "You would have bet on mass arrests, the government in jail, everything banned, reformers thrown out of their jobs, out of the universities, the whole Soviet thing, with accordion bands playing Beatles songs." Yet, as the darker '70s begin to unfold, and Jan becomes a supporter of the underground Czech band The Plastic People of the Universe, things become clearer for him.

Max makes a visit to Prague to see Jan, but still speaks from his heart as an unrehabilitated communist. "If it wasn't for the 11 million Soviet military dead," Max lectures a dejected Jan, "your little country'd be a German province by now."

It's Stoppard's strength as a writer that Max never becomes a cliché or cartoon. For Max, who is "as old as the October Revolution," his commitment to the cause is forthright and sincere. Yet even this Oxbridge titan will make a grudging peace with the historic inevitability of communism's collapse (belatedly celebrated in the bacchanalian last scene where Max's daughter, Esme, [Sinead Cusack] and Jan finally see the Rolling Stones play at Strahov).

Trevor Nunn's production of Rock-n-Roll is occasionally plodding, but he's assembled a marvelous cast to populate Stoppard's world. Cox is a formidable Max, lacing his cultured, ironic observations of the world with lacerating invective whenever his political philosophy is questioned. Sewell is superb as Jan, a well-crafted surrogate for Stoppard himself, had the Czech-born playwright found himself back in Prague during that grim period. Cusack expertly takes on two roles: Max's wife, Eleanor, a cancer-ridden classics scholar, and daughter Esme, a defunct lovechild trying to find a place for herself in the world.