Beginning in October 2017, the National Academies of Sciences, Engineering, and Medicine organized a set of workshops designed to gather information for the Decadal Survey of Social and Behavioral Sciences for Applications to National Security. The first workshop focused on changing sociocultural dynamics and implications for national security, and this publication summarizes the presentations and discussions from this workshop.Table of ContentsFront Matter1 Introduction2 Linking Culture, Language, Behavior, and Data3 Triangulation of Data Sources and Research Methods4 The Challenge of Multiple Levels of AnalysisAppendix A: Statement of Task for the Decadal Survey of Social and Behavioral Sciences for Applications to National SecurityAppendix B: Workshop AgendaAppendix C: Participants ListAppendix D: Biographical Sketches of Steering Committee Members and Presenters