Abstract: The use of a monostatic radar configuration limits the ability of an Inverse Synthetic Aperture Radar (ISAR) system to image targets moving along the radar Line Of Sight (LOS). By employing bistatic geometries this limitation may be overcome. This paper analyzes the echo model of bistatic ISAR. The imaging theory, azimuth resolution, target size limitation and sampling rate of bistatic ISAR are studied in detail, and the analytical solutions are obtained. The computer simulation images are presented.