We have already encountered the sampling theorem and, arguing purely from a trigonometric-identity point of view have established the Nyquist sampling cri-terion for sinusoidal signals. However, we have not fully addressed the sampling of more general signals, nor provided a general proof. Nor have we indicated how to reconstruct a signal from its samples. With the tools of Fourier transforms and Fourier series available to us we are now ready to nish the job that was started months ago.