This Glossary of Failure is one of the results of the Research Project «Failure. Reversing the genealogies of unsuccess; 16th-19th CenturiesFunded by the European Union. Within the framework of a complex and interdisciplinary investigation such as this, born from the convergence of different fields of knowledge such as history, philology, art history, and philosophy, the aim of this volume is to address, in a predominantly conceptual way, the polysemy of the very notion of failure. However, a conceptual approach does not imply an abstract consideration of the logical characteristics of failure, independent of any context or specific use of the term. Let us not forget, in fact, that even Hegel had to rewrite his Science of logic based on the scientific discoveries and political events of their time. Therefore, all the entries in this glossary, while starting from an etymological approach, also address the literary, artistic, scientific, and—of course—philosophical manifestations and applications of each of the notions.