Abstract : The two major research efforts were in the areas of (1) nonminimum-phase linear and nonlinear time-varying systems, and (2) multiple-loop single input-output systems. In both areas, the objective was to develop synthesis techniques to achieve assigned system performance specifications, despite significant uncertainty in a constrained part (plant) of the system. In the first area, it was necessary to first solve the optimal linear time invariant nonminimum-phase problem. This enabled the solution of the linear time-varying nonminimum-phase problem. Progress was made on the nonlinear time-varying case. In the second area, an optimal design technique was completed for the simplest (two-loop) noncascade system, and it appears promising that the same design philosophy can be used for more complex structures.