The paper describes the True Digital Control (TDC) design philosophy for linear, single input, single output (SISO) systems described by the backward shift (z^-1) and delta (δ) operator transfer function model; and outlines a Computer Aided Control System Design (CACSD) procedure based upon this design philosophy. The control system design analysis used in the CACSD procedure is based on the definition of suitable Non-Minimum State Space (NMSS) forms for the z^-1 and δ models, which allow for state variable feedback (SVF) control involving only the measured input and output variables, together with their stored past values. The resulting 'Proportional-Integral-Plus' (PIP) control systems then provide either SVF pole assignment control or optimal LQG control without resort to the complexity of state reconstructor (observer) design. The paper outlines the major stages in the TDC design: from model identification and parameter estimation; through PIP control system design and the evaluation of these designs in the presence of uncertainty, to their implementation in fixed gain, self-tuning of self-adaptive form.