The medicine of Aulus Cornelius Celsus (flourished in the first third of the first century AD) is not a textbook and does not belong to any canon. Reading the work from beginning to end is challenging even for medical historians. However, anyone studying the history of medicine in antiquity cannot overlook Celsus, even though the author presumably did not work professionally as a physician. The eight books contain countless witty remarks and historical gems. The present selection includes the prologues, the most important passages from the presentation of theoretical and clinical subjects, the most original case descriptions, and also the essential contributions of the work to terminology and ethics in medicine. Numerous original texts are presented for the discussion of sources and reception in antiquity and the Middle Ages.