The role of requirements in systems development is perhaps one of the most contentious issues in modern systems engineering. Some believe that formal requirements, particularly text-based requirements, are no longer necessary as part of modern development methodologies. Yet, others point out that the lack of adequate requirements has been shown to be one of the principal causes of project failure. So, who is correct? Why would a project team bother to expend all that effort and angst in developing requirements if they aren’t necessary? This presentation will summarise the opposing perspectives and highlight the importance of a robust set of concepts, needs, and requirements in the design and development of a system of interest, as well as in the critical activities of verification and validation.