Electron backscattering diffraction (EBSD) has become a technique of great importance in scanning electron microscopy. The diffraction patterns obtained by this method are of value in identifying phases and in determining the orientation of samples. The technique was initially developed about thirty years ago and has enjoyed widespread use in the last decade or so. It is therefore something of a surprise that there do not exist computer programs that simulate the patterns well. In fairness, we must make it clear that a number of programs exist and others are being implemented, which represent important steps towards the simulation of EBSD patterns. However, as we hope these notes will make clear, a satisfactory simulation will be very difficult and we are not aware of any existing or forthcoming program that does a job that can be guaranteed to give accurate values for the intensities in the experimental patterns.