We return now to the task of constructing a more realistic simulation of populations like the !Kung, so that we can exploit these simulations to tell us about aspects of the population structure that are otherwise invisible. The model constructed in this chapter will be the best version of simulation used in this work, although I would not, of course, argue that it is the best and most realistic simulation that could possibly be constructed to mimic the !Kung. All simulations are simplifications, since in model construction there is a trade-off between theoretical clarity, generally achieved by making the model as simple as possible, and precision in tailoring the model to the target population, which usually requires introducing complexity. In general, AMBUSH has been constructed to operate as simply as possible, so that the outputs can be understood in terms of the interactions of a few processes. Nevertheless, the procedures used must be understood in order to interpret the outputs; these procedures are sufficiently complex that this chapter is devoted to explaining them. The first section of this chapter will explain how AMBUSH arranges marriages and generates fertility within those marriages. We will then look at the input probabilities to the simulations and the outputs of those variables (as they interact) and others produced directly by the input. Along the way, we see some of the implications of the solution of the “two-sex” problem for men’s fertility and the growth rate of the population as measured for the two sexes.278