This documented briefing describes RAND research that supported the 1998 Defense Science Board (DSB) Summer Study on Joint Operations Superiority in the 21st Century: Integrating Capabilities Underwriting Joint Vision 2010. RAND supported the DSB through both exploratory analysis and high-resolution simulation-based analysis; this document only covers the high-resolution work, notably simulation experiments to help explore and assess Joint operational concepts. It builds on related work done by the authors for the DSB effort, Tactics and Technology for 21st Century Military Superiority (DB-198-A). The current effort draws on outcomes of other DSB studies, discussions with warfighters, and interactions with DSB members, to define a range of different Joint operational concepts that could be applied to a future (2010-2015) notional, high-intensity, quick-reaction scenario. The strengths and weaknesses of these concepts were explored using man-in-the-loop, high-resolution, stochastic constructive simulation in the context of a single basic scenario with a number of variations. The authors' intention in this work was to (1) provide insights and inputs for a broader, exploratory RAND analysis for the DSB, (2) increase dialogue among conceptualizers, users, and developers, and (3) suggest ideas to help the DSB take JV 2010 to the next step.