A letter dated December 21, 2011, to National Academy of Sciences President Dr. Ralph Cicerone from the Chief of Naval Operations, ADM Jonathan W. Greenert, U.S. Navy, requested that the National Research Council's (NRC's) Naval Studies Board (NSB) conduct a study to examine the issues surrounding capability surprise—both operationally and technically related—facing the U.S. naval services. Accordingly, in February 2012, the NRC, under the auspices of its NSB, established the Committee on Capability Surprise for U.S. Naval Forces. The study's terms of reference, provided in Enclosure A of this interim report, were formulated by the Office of the Chief of Naval Operations (CNO) in consultation with the NSB chair and director. The terms of reference charge the committee to produce two reports over a 15-month period. The present report is the first of these, an interim report issued, as requested, following the third full committee meeting. The terms of reference direct that the committee in its two reports do the following: (1) Select a few potential capability surprises across the continuum from disruptive technologies, to intelligence inferred capability developments, through operational deployments and assess what U.S. Naval Forces are doing (and could do) about these surprises while mindful of future budgetary declines; (2) Review and assess the adequacy of current U.S. Naval Forces' policies, strategies, and operational and technical approaches for addressing these and other surprises; and (3) Recommend any changes, including budgetary and organizational changes, as well as identify any barriers and/or leadership issues that must be addressed for responding to or anticipating such surprises including developing some of our own surprises to mitigate against unanticipated surprises. Capability Surprise for U.S. Naval Forces: Initial Observations and Insights: Interim Report highlights issues brought to the committee's attention during its first three meetings and provides initial observations and insights in response to each of the three tasks above. It is very much an interim report that neither addresses in its entirety any one element of the terms of reference nor reaches final conclusions on any aspect of capability surprise for naval forces. The committee will continue its study during the coming months and expects to complete by early summer 2013 its final report, which will address all of the elements in the study's terms of reference and explore many potential issues of capability surprise for U.S. naval forces not covered in this interim report.