Long ago, writing surfaces were so highly valued that they were often used more than once. Palimpsest in its original use referred to an early form of recycling in which an old document was erased to make room for a new one when parchment ran short. (The word is from the Greek palimpsēstos, meaning “scraped again.”) Fortunately for modern scholars, the erasing process wasn’t completely effective, so the original could often be distinguished under the newer writing. De republica, by Roman statesman and orator Cicero, is one of many documents recovered from a palimpsest. Nowadays, the word palimpsest can refer not only to such a document but to anything that has multiple layers apparent beneath the surface.