The Notory Art of Shorthand (Ars notoria notarie), an important yet understudied late medieval work, is newly edited here and presented for the first time in English translation along with an introduction and commentary. This unique treatise on shorthand writing is a hybrid of literary genres that sheds much light on late medieval scribal culture. Following in a medieval tradition of works such as the Secret of Secrets, the innovative Ars notoria notarie points forward to early modern hermetic writers such as Agrippa von Nettesheim and John Dee, the latter having owned one of the three manuscripts of the work. The Ars notoria notarie relates to disciplines ranging from paleography to magic. It has multiple identities: a unique branch of one of the most popular magic treatises of the Middle Ages, the Ars notoria; a rare report on medieval paleography and the notarial trade; an exposé of a unique medieval cipher based on the famous Tironian notes; an eclectic university text bringing together authorities from Pliny and Aristotle to Donatus and Bede; a remarkable source for the liturgy of Thomas Becket; and, finally, a distinctive contribution to the epistolary genre known as the mirror for princes.