Usability engineering is a professional discipline that focuses on improving the usability of interactive systems. It draws on theories from computer science and psychology to define problems that occur during the use of such a system. Usability Engineering involves the testing of designs at various stages of the development process, with users or with usability experts. The history of usability engineering in this context dates back to the 1980s. In 1988, authors John Whiteside and John Bennett—of Digital Equipment Corporation and IBM, respectively—published material on the subject, isolating the early setting of goals, iterative evaluation, and prototyping as key activities. The usability expert Jakob Nielsen is a leader in the field of usability engineering. In his 1993 book Usability Engineering, Nielsen describes methods to use throughout a product development process—so designers can ensure they take into account the most important barriers to learnability, efficiency, memorability, error-free use, and subjective satisfaction before implementing the product. Nielsen’s work describes how to perform usability tests and how to use usability heuristics in the usability engineering lifecycle. Ensuring good usability via this process prevents problems in product adoption after release. Rather than focusing on finding solutions for usability problems—which is the focus of a UX or interaction designer—a usability engineer mainly concentrates on the research phase. In this sense, it is not strictly a design role, and many usability engineers have a background in computer science because of this. Despite this point, its connection to the design trade is absolutely crucial, not least as it delivers the framework by which designers can work so as to be sure that their products will connect properly with their target usership.[1]