This thesis is an attempt to clarify a concept we are all familiar with, engineers and non-engineers alike. It shows that, behind the first impression of familiarity, there is a wide range of intuitions about failure which are not easily reconciled. While the ensuing ambiguities and lack of clarity may be tolerated in ordinary circumstances, engineers strive for precision and efficiency. These qualities become even more relevant given that engineering activities are increasingly carried out by multidisciplinary and multicultural teams. The chapters included in this thesis illustrate that pursuing conceptual clarification may result in valuable contributions to the existing literature. The identification of tacit assumptions that, so far, have gone undetected can help bringing some degree of order and unity to discussions that have shown a tendency towards fragmentation along disciplinary boundaries. As a whole, these chapters constitute the preliminaries of a conceptual framework that, once supplemented with additional engineering and philosophical contributions, may embrace the multiple facets of failure; a rather complex tangle of phenomena which, despite engineers’ efforts to rein it in, is not going to disappear from the engineering agenda anytime soon.