I was a college sophomore in April 1971, still mourning the death of Jimi Hendrix, when I learned that a campus organization to which I belonged was being spied on by the Federal Bureau of Investigation. The news landed in the mailbox of the Black Student Union — at what is now known as Widener University, not far from Philadelphia — in an envelope stuffed with documents that had been stolen from an F.B.I. office in nearby Media, Pa.

The burglars referred to themselves as the Citizens Commission to Investigate the F.B.I. The streets were soon teeming with agents who tried in vain to find them. But the mailings continued, reaching news organizations, members of Congress and people like us who had been placed under surveillance.

A fledgling organization at the time, the Black Student Union was hardly a hotbed of revolutionary agitation. We sponsored cultural events, played a bit of a role in campus politics, recruited black students and threw the occasional party. We were flattered to find that the boogeyman of the era, J. Edgar Hoover, found us worthy of surveillance; it gave us more significance than we deserved and seemed to place us on the level of fearsome outfits like the Weathermen and the Black Panthers.

The excitement turned to chagrin as we read the documents. The F.B.I. described us as an incompetent and “basically dormant” group that had displayed no “radical or militant ideas.” Based on that judgment, the bureau should have focused its attentions elsewhere. Instead, the Philadelphia office said that it would develop informants on the Black Student Union’s leaders so that it could become “aware of their identity and background.” In other words, innocence was no defense; people who came under unwarranted scrutiny might never escape it.