This AP photo appeared in today’s New York Times next to a story about the end of the BBC’s shortwave service. It caught my eye not because the man seated at the microphone is John Dos Passos—I would have never known it was him without the caption—but because of the poster that hangs over his shoulder, which reads “be like dad, Keep Mum!” That poster was part of a WWII campaign in Britain against loose talk—you can just make out the tagline running along the poster’s bottom edge, which reads, “Careless Talk Costs Lives.”

If you’ve read the first volume of Javier Marías’s excellent Your Face Tomorrow, you might remember the Keep Mum poster; it’s one of many from the campaign that is reproduced in the novel’s pages (this one shows up on page 320). If you haven’t, here’s some of what Peter Wheeler, one of the book’s characters, has to say about it:

I don’t think there was ever a campaign like this one against “careless talk,” in which they not only put civilians on guard against possible spies, but recommended silence as the norm: people were prevailed upon not to speak, they were ordered, indeed exhorted, to keep silent. Suddenly people were made to see their own language as an invisible enemy, uncontrollable, unexpected and unpredictable, as the worst, most murderous and most fearful of enemies, like a terrible weapon which you, or anyone, could activate and set off without ever knowing when it might unleash a bullet, or if it would be transformed into torpedoes that would sink one of our battleships in the middle of the ocean thousands of miles away, or into bombs from a Junkers that would strike with deadly accuracy at our neighbourhoods and our houses, or fall on those military targets that most needed to be safeguarded and defended, on the most secret and most camouflaged and most vital of targets. I don’t know if you quite realise what it meant, Jacobo: people were warned against using their main form of communication; they were made to distrust the very activity in which most people naturally indulge and always have indulged, without reserve, at all times and in all places, not just in this country and at that particular time; it made an enemy of what most defines and unites us: talking, telling, saying, commenting, gossiping, passing on information, criticising, exchainging news, tattle-taling, defaming, slandering and spreading rumors, describing and relating events, keeping up to date and putting others in the picture, and, of course, joking and lying. That is the wheel that moves the world, Jacobo, more than anything else: that is the engine of life, the one that never becomes exhausted and never stops, that is its life’s breath. And suddenly people were asked to turn it off, that engine, to stop it breathing.