The practice of ancient magic was quite like that of modern cooking. Just as today, while anyone can cook but only some can cook well, anyone in the ancient world could make a simple amulet or castigate a wayward demon, but only a few specialized in such activities and achieved superior results. And, just like modern cooks, such ancient practitioners had their own private note-books, where their painstakingly accumulated secrets were preserved -- collections of recipes, hints, notes, and ideas, whether borrowed or adapted from others or independently developed. Each recipe was tested, improved upon, and in some cases passed on to clients, colleagues, disciples, or successors. Being the main vehicle for the transmission of magical lore, such books often were the target of suppression, especially, but not exclusively, by Christians (cf. Acts 19:19). Fortunately, some of these collections have survived. Since these were normally written on papyrus, a perishable organic material, the specimens which did survive all come from the dry sands of Egypt, and are written either in Greek or in Egyptian. However, similar recipe-books -- in Hebrew, Aramaic, and Arabic -- were found in the Cairo Genizah (the used-paper store-room of a medieval synagogue in Cairo, Egypt), and numerous medieval manuscripts -- in Greek, Latin, Arabic, and many other languages -- attest to the vitality of such recipe-books in various forms throughout the Middle Ages.
Being in large part the working-manuals of individual practitioners, such collections vary greatly in length and quality -- from an individual recipe scribbled upon a small slip of papyrus torn off a previously used scroll, to large anthologies with dozens of recipes, meticulously copied and lavishly annotated. Moreover, because they were meant for their owners' private use, they often contain such brief instructions as "(repeat this) three times," or an "etc.," when only a few words of a well-known (to the owner, that is) invocation are written down. Such abbreviated notes, and the lack of a systematic ordering of the spells -- not to mention a preface or an index -- would have made such a recipe book hard to use for anyone who was not intimately familiar with its contents. In rare cases, the recipes were written in a special cipher, apparently invented by one practitioner for that specific purpose, in which case no outsider could make any use of the encoded recipes.
Unfortunately, recipe books never mention their owners' names, though in some cases the identity of the owner can be deduced, at least roughly, from the papyrus' provenance. In rare cases, the book's owner noted where a specific recipe came from, and such notes as "This is a recipe which a physician in the Oxyrhynchite nome gave me" (PDM xiv. 528), or "I have heard from a certain man of Herakleopolis that..." (PGM V.372), can teach us something about the lines of transmission of the recipes themselves. In one case, we even have a practitioner's brief memo to himself (Suppl. Mag. I, 5): "The amulet against tonsillitis for the gold plate -- write it on a slip of papyrus, word for word, and send it to Sarmates," another indication of how such recipes were disseminated.
Go on to the Recipe-Books display.