Classical high-performance filters are explored, including Butterworth, Chebyshev, Bessel, and other responses. Properties of interest include fast roll-off, flatness of the passband gain, overshoot and ringing of the step response, and group delay of the phase response. Pole locations are found, and simple MATLAB scripts are used to generate and plot these responses. A third-order Butterworth filter is designed using op-amp networks.