The document discusses computer simulation as a tool for process improvement. It defines computer simulation, outlines the basic steps which include defining the problem, mapping the process, defining inputs, building a model, validating the model, performing simulations, and interpreting results. Reasons for using simulation include testing changes without risk or time, understanding bottlenecks, and verifying expected improvements. Simulation should not be used without proper training or understanding, or when simpler methods can be used.