Mitford scrutinizes other forms of media, too, often focusing on how they handle (or in some cases, staunch) the flow of information. Interviewing the literary radical George Jackson, she presses him on how he managed to publish a book in prison, despite abundant censorship. (The book, Soledad Brother, comprised letters that Jackson mailed from jail. The guards altered or confiscated many, but eventually Jackson’s lawyers managed to prohibit such tampering.) One of her finest pieces examines NBC’s decision to block production of a television special meant to clarify details about a particular sexually transmitted disease. Before doing so, the network ordered a series of cuts and substitutions that range from amusing to problematic:

“As is your custom, please exercise caution when showing the interns staring appreciatively at the group of nurses passing by. In addition, please eliminate Dr. Tyler’s speech, ‘If she is not anybody’s kin—and nobody’s sister—I would like to scrub with her.’”…“Please delete ‘a case of syphilis’ and substitute ‘this disease.’ ”

Mitford provocatively titles her article “Don’t Call It Syphilis,” both echoing and rebutting NBC’s efforts to hide unpleasant facts.

Tracking truths is Mitford’s passion, and her notes reveal her despair when she misses an especially good one. After she published her piece on the Famous Writers School, for example, she found out the teachers had been sending pupils cleverly camouflaged form letters. Having overlooked this tidbit gave her nightmares for years. And yet, for someone so devoted to facts, she is surprisingly enthusiastic about strategic mendacity: “Ethics is not one of my strong points,” she explains. She continues:

In general, I think that if you have promised anonymity to the person you are interviewing, or if it is agreed in advance that he is speaking “off the record,” such agreement should be respected. Better, however, to steer him away from such untoward thoughts, which can often be done by fast and dexterous talk about the matter at hand, so that the problem does not arise.

Should modern readers feel uneasy about Mitford’s occasionally underhanded methods? To be honest—as she sometimes wasn’t—it’s hard to remain indignant in the face of her reportage, which illustrates the utility of the artful lie in unearthing more pernicious ones. Besides, her trickery is so entertaining that we inevitably chuckle even as we cluck. At one point, Mitford was researching the corruption of American prisons in preparation for her book on the subject, and sought access to back issues of The Grapevine, an insider trade magazine. She knew the publication was hostile to her journalism (“Her kind of reporter is one of the realities of life in these troubled times,” an article had lamented). And so she had her assistant write the editors a fawning letter under the guise of an aspiring corrections officer:

I have long felt that my education here has been jammed into a liberal mold of propaganda. I see your publication as a credible news source of our profession undistorted by the rampant irresponsible and unrealistic biases of the media and campus liberals.

Mitford tweaked the fake name her assistant had chosen to Kenneth from Karl—the original, she worried, might sound subversive—and dispatched the note. The magazine not only provided Mitford with back issues but also reprinted the letter for the benefit of all its readers, eager to publicize its popularity among the next generation of corrections hopefuls.

All this strikes Mitford as a hoot. In Poison Penmanship, she never comes off as morally superior. Rather, she’s both discriminating and flawed, a good and bad cop united into a gleeful one-woman force. She doesn’t write so much as crow—whether about other people’s schemes or her own—and she leavens her sentences with stylistic surprise. Her passion for justice compares with her passion for mots justes, and, like some of us, she loves a good pun. Mitfordian missiles such as “I ain’t gonna study Waugh no more” will likely make such people cackle and slap their knees.

Mitfordian misfires—the messy phrase, the ill-chosen word—are rare but bothersome, like mosquitoes that have managed to penetrate high-quality netting. I wondered why her technical flaws made me flinch, and realized that her fault-finding energy, along with her uppity tone, is contagious. After hitting upon the phrase “As my firstborn, I still feel some maternal affection for it,” I penned indignantly in the margin: “Now, Jessica! Unhinge that dangling modifier and reattach it somewhere more appropriate!”

Abigail Deutsch is a writer who lives in New York. Her work appears in The Village Voice, n+1, Bookforum, Poetry, and other publications.