From Abracadabra to the Avada Kedavr and Rennervate used in the Harry Potter books, everyone has become familiar with magic words, although novels, films, and comic books can provide only a simplified, distorted version of them. Shouted, whispered, chanted, recited, or muttered by a magician, sorcerer, or witch—using peculiar and even incomprehensible words to obtain supernatural effects—these perpetually evolving spells come down to us from the dawn of time. Thanks to the efforts of the scholars from a variety of disciplines, we now have a corpus consisting of tens of thousands of accounts at our disposal. These phrases can be found in charms (from the Latin carmen, meaning “song”), orisons, blessings, conjurations, and medical prescriptions. Orisons are magic prayers that conceal their true nature behind a Christian exterior, most often through references to Jesus, Mary, the evangelists, and so on. Blessings can be pagan or Christian, but either way they share the same structure: they are used to summon good fortune on an individual; they are the opposite of curses. Conjurations are used to summon supernatural beings whose assistance is required as well as to perform the exorcisms necessary to banish the malevolent entities embodied in misfortunes. These entities are most often encountered in remote solitudes and deserted regions where men rarely travel. As for the short notes still known today as brevets in France, they are most often found on amulets of parchment or paper that contain Kabbalistic phrases that have been encrypted through the use of characters known as “Solomonic writing,” “Ephesian letters,” or “unknown scripts.” All these strange signs are called caracteres in Latin, a term I will use to avoid creating any confusion. A scholar wrote this about Ephesiae litterae in 1717: “They plunge the soul of those who hear them into terror.”  Hebrew letters were also used because, according to the Pseudo–Arnaldus de Villanova,  they were the most effective (“Sihabet literas hebraycas, efficassisimum est opera”). But Saint Jerome had already spoken in his own time about magicians who used every means to impress their customers: the less these customers understood, the more they found admirable. One of the purposes of magical phrases and words was the protection of people and property. It involved preventing something from happening or halting an action already at work—a fire or the effect