A gray scale bistable electro-optic display is driven by storing a look-up table containing data representing the impulses necessary for transitions, storing data representing at least an initial state of each pixel of the display, receiving an input signal representing a desired final state of at least one pixel of the display; and generating an output signal representing a pixel voltage to be applied to the pixel. Compensation voltage data representing a compensation voltage is stored for each pixel, the compensation voltage for each pixel being calculated dependent upon at least one impulse previously applied to that pixel, and the pixel voltage is the sum of a drive voltage determined from the initial and final states of the pixel and the look-up table, and a compensation voltage determined from the compensation voltage data for the pixel. Other similar methods for driving such displays are also disclosed.