The DualI/DualPC software for optimal control models: User’s guide. This is a user’s guide for the Duali/Dualpc software for quadratic-linear optimal control models. Duali (which is pronounced “dual I”) provides a graphical interface for deterministic, passive and active learning stochastic models as well as solvers for deterministic models and for passive learning stochastic models. It does not yet contain a solver for adaptive control models. However it does provide a procedure to export a file, which can be used to solve adaptive control models with the Dual or Dualpc software packages. Duali/Dualpc runs under Windows 95 or later and Windows NT 4.0 or later on personal computers. Duali is written is the C language. Dualpc is written in Fortran using Microsoft PowerStation. Duali has been developed and compiled using Microsoft Visual Studio 6.0, which contains Microsoft Visual C++ Ver. 6.0. This guide is for Version 0.321 of Duali and version xx of Dualpc.