Decades ago, simulation was famously characterized as a "method of last resort," to which analysts should turn only "when all else fails." In those intervening decades, the technologies supporting simulation-computing hardware, simulationmodeling paradigms, simulation software, design-and-analysis methods-have all advanced dramatically. We offer an updated view that simulation is now a very appealing option for modeling and analysis. When applied properly, simulation can provide fully as much insight, with as much precision as desired, as can exact analytical methods that are based on more restrictive assumptions. The fundamental advantage of simulation is that it can tolerate far less restrictive modeling assumptions, leading to an underlying model that is more reflective of reality and thus more valid, leading to better decisions.