Requirements Engineering (RE) has grown from its humble beginnings to embrace a wide variety of techniques, drawn from many disciplines, and the diversity of tasks currently performed under the label of RE has grown beyond that encom-passed by software development. We briefly review how RE has evolved and observe that RE is now a collection of best practices for pragmatic, outcome-focused critical thinking-A pplicable to any domain. We discuss an alternative perspective on, and de-scription of, the discipline of RE and advocate for the evolution of RE toward a discipline that supports the application of RE prac-tice to any domain. We call upon RE practitioners to proactively engage in alternative domains and call upon researchers that adopt practices from other domains to actively engage with their inspiring domains. For both, we ask that they report upon their experience so that we can continue to expand RE frontiers. © 2017 IEEE.