Control System Design methods are presented in terms of optimization techniques that incorporate Multi-Objective design criteria. Computer-Aided Control System Design (CACSD) environments make the approach easy-to-use and accessible to the practising control engineer. Two CACSD environments have been developed using different versions of the MATLAB package, one interfacing the ADS optimization package to an upgraded FORTRAN version of MATLAB, the other using Non-linear Programming algorithms coded in the PRO-MATLAB command language. In both environments, optimization problems are entered interactively and in a flexible manner using simple interpreted commands and programs. A Control System Design method has been implemented using optimal control theory and integral quadratic measures of control. The theory has been developed to incorporate a large number of design options, control structures and disturbance types. An evolutionary design process is used so that the control order and number of design criteria are systematically increased to incorporate more complex control structures and a wide set of performance objectives. In the later stages of this evolutionary design process, a Multi-Objective design strategy, known as the Goal Attainment method, is used to address multiple performance objectives.