The relationship between theory and practice, between norms indicated in a text and their extra-textual application, is one of the most fascinating issues in the history and theory of science. Yet this aspect has often been taken for granted and never explored in depth. The essays contained in this volume provide a multi-layered and nuanced discussion of this relationship as it emerges in ancient Greek and Roman culture in a number of fields, such as agriculture, architecture, the art of love, astronomy, ethics, mechanics, medicine and pharmacology. The main focus is on the textuality of processes of transmission of knowledge and its application in various fields. Given that a text always contains complex and destabilizing aspects that cannot be reduced to the specific subject matter it discusses, to what extent can and do ancient texts support extra-textual applicability?