This book on uncertainty is the beginning of a series titled “N ew Horizons in Managerial and Organizational Cognition”. We asked Frances Milliken and Ge rard P. Hodgkinson, two well-known scholars who have made important contributions to ou r understanding of uncertainty to help introduce the effort. The brief bios found at the end o f this volume cannot do justice to the broad range of their contributions, but our conversation gi ves a flavor of the kind of insights they have brought to managerial and organizational cognition (M OC). The editors thank them for helping launch the series with a decisive exploration of what d efining uncertainty involves, how that might be done, why it is important, and how the task is ch anging. We were interested to discover that all five of us a re currently involved in research that considers the nature and impact of uncertainty, and we hope that readers similarly find that pa ying attention to uncertainty contributes to their current pro jects. Working together, we can further expand understanding of organizational settings and effective action for both researche rs and practitioners.