Bistatic Synthetic Aperture Radar represents an active research and development area in radar technology. In addition, Bistatic and Multistatic SAR concepts are tightly related to formation flying and distributed space missions that also represent the new space-based remote sensing and surveillance frontiers. This chapter introduces Bistatic SAR, in particular by comparing its peculiarities, operation and performance with respect to conventional monostatic SAR. Some basic concepts of bistatic SAR image formation and the main elements of bistatic SAR geometry are preliminary presented. Performance parameters are then analyzed, including geometric resolution, radiometric resolution and bistatic radar equation. Special emphasis is placed on analytical methods to evaluate the effects of bistatic SAR geometry on image resolution. Further implementation issues, such as footprint, time and phase synchronization are also pointed out. The analysis of past bistatic radar and bistatic SAR experiments and proposed spaceborne bistatic SAR missions supplies essential information to understand how these issues have been faced and can be potentially solved in ongoing and future operational systems. Finally, several scientific applications of bistatic SAR are outlined taking advantages of different techniques and methods.