System failure engineering may encompass reliability, safety, security, maintainability, risk, and quality control. In this paper we pay a unified view, i.e., a failure-oriented view to system failure engineering. The notion of failure can be represented in terms of fuzzy sets and widely interpreted. We then discuss various application aspects of fuzzy methodology in system failure engineering, which include fuzzy methodology in fault diagnosis, in probist systems, in structural reliability, in software reliability, in human reliability, in safety engineering, in security engineering, in risk engineering, and in quality control, as well as profust, posbist, and posfust reliability theories. Engineering case studies and mathematical problems raised by applications of fuzzy methodology in system failure engineering are also addressed in this paper.