The interrobang is one of the few marks in this collection with a birthday and an inventor. It was created in 1962 by Martin K. Speckter, a New York advertising executive who noticed a gap in punctuation and set out to fill it. He wanted a single mark for a particular kind of sentence: the rhetorical question asked in disbelief, the one that is half a question and half an outcry. Ordinary punctuation forced a writer to choose between a question mark and an exclamation point, or to pile them awkwardly together. Speckter proposed one character that was both at once, fusing the two marks into a single glyph.

For a moment it seemed poised to catch on. Some typewriters of the 1960s offered the key as an option, and in 1968 Remington announced a model with an optional interrobang key, a small sign of real commercial interest. But the key came at extra cost, and the extra-cost option never caught on. The mark that a manufacturer was willing to build simply failed to find enough writers willing to pay for it, and the interrobang slipped out of everyday use almost as quickly as it had arrived.

It did not quite die, though, and its survival is a small parable of the digital age. Unicode, the vast standard that assigns a code point to every character worth encoding, keeps the interrobang alive with its own code point, a permanent address in the world's character set even though hardly anyone types it. A mark that could not survive the economics of the typewriter found refuge in software, preserved for whoever might want it. Even its name is a fusion, matching its form. It splices interro, from interrogate, onto bang, which is the proofreader's own word for an exclamation point. So the character is a marriage twice over: two marks joined into one shape, and two words joined into one name, all in service of a tone we all recognise but rarely had a way to write.