In October 2023, an e-mail pinged onto Federica Nicolardi’s phone with an image that would transform her research forever. It showed a fragment of a papyrus scroll that had been burnt in the eruption of Mount Vesuvius in ad 79. The scorched scroll was one of hundreds discovered in the remains of a luxury Roman villa in Herculeaneum, near Pompeii in Italy, in the eighteenth century. Attempts over the centuries to peel apart the scrolls’ fragile, carbonized layers left many in pieces, and scholars...