We describe four computer packages for interactive computer-aided design of control systems. DIGICON (digital control) is a computer aid to the design of digital controls for single-input single-output (SISO) systems using the state-space techniques of pole and zero assignment. CONCON (continuous control) is a similar package for the design of SISO continuous systems using the same techniques. The program DOPTICON (discrete optimal control) is a computer aid for the design of discrete optimal control systems using the linear quadratic Gaussian (LQG) theory and OPTICON (optimal control) is its continuous-time counterpart. All four packages contain algorithms for computation of the poles and zeros of the resulting designs as well as the evaluation of the transient responses.