Uncertainty is prevalent characteristic of contemporary life, and a central challenge of HCI. This one-day workshop will explore how HCI has and might continue to engage uncertainty as a generative feature in design, as opposed to a force to mitigate and control. We hope to convene researchers from broad ranging areas to explore the many ways in which uncertainty appears in our research and the different types of responses that HCI has to offer. There is an incredible variety of conceptual formulations of uncertainty and related ideas like risk, ambiguity, and suspense that raise both difficult challenges as well as significant opportunities for creative engagement with societal challenges. During the workshop, we won't seek to "solve" uncertainty but rather expand the ways in which we think about and navigate it. In doing so, we will experiment with and contribute to new practices, methods, and concepts for embracing uncertainty. Outcomes of the workshop will include documentation of..