The Arab Spring saw more than 300,000 protesters in Cairo’s Tahrir Square bring down Hosni Mubarak. But did these protesters represent the average Egyptians who stayed home? Writing about another equinox — the 1968 Prague Spring that introduced liberal reforms to communist Czechoslovakia and provoked a Soviet crackdown — Jonathan Bolton examines in “Worlds of Dissent” how revolutionaries speak for a nation.

“We speak of ‘the dissidents’ as if we knew who they were and, indeed, as if they knew who they were,” Bolton writes. “Was it meaningful, even possible, to bracket off a small group of people and to judge the rest of society using them as the moral measuring stick?”

In 1970s Czechoslovakia, this measuring stick turned out to be a rock-and-roll band. Opposition leader Vaclav Havel championed the Plastic People of the Universe, long-haired hippies who played Frank Zappa-inspired progressive rock. The playwright and future Czech president “saw them as members of an innocent youth culture — uncompromised, uninterested in the corrupt world of ‘politics,’ and in a real sense inarticulate,” Bolton writes. This assessment wasn’t just condescending but also inaccurate. The Plastics — “neither fully tolerated nor systematically harassed by the police, a status that gave their performances an undeniable frisson and intensified the audience’s feelings of freedom and solidarity” — were popular, but they weren’t angels.

Still, when the band’s saxophonist and artistic director were put on trial in 1976 for disturbing the peace, Havel marshaled an uproar that produced Charter 77 — the Czechoslovak opposition’s declaration of independence from communist oppression. But by stereotyping musicians as unsophisticated flower children, Bolton explains, Havel unwittingly overlooked the underground’s powerful critique of the regime.

Although “Worlds of Dissent” is weighed down by endless parsing of historical detail, the author’s nuanced view of Czech activism is helpful in understanding the Middle East’s blithely named “Facebook revolutions” as they enter their second year.

’Worlds of Dissent: Charter 77, The Plastic People of the Universe, and Czech Culture under Communism’ by Jonathan Bolton (Harvard University Press)