<b>A Review of Friction Stirs Welding</b> Through this paper an attempt is made to study and review a special welding technology of friction stir welding FSW which is a solid state joining process. Friction Stir Welding FSW is a recent advanced technique, invented by The Welding Institute TWI in 1991, that utilizes a nonconsumable rotating welding tool to generate frictional heat and plastic deformation at the welding location thereby, affecting the formation of a joint while the material is in the solid state. In particular, FSW can be used to join high strength aerospace aluminum alloys and other high temperature metallic alloys that are difficult to weld by conventional fusion welding method. FSW is considered to be the most significant development in metal joining process in a decade The comprehensive body of knowledge that has built up with respect to the friction stir welding FSW of aluminum alloys. This study addresses the current state of understanding and development of the FSW process. The principles of weld formation, welding parameters, design principles, including metal flow and thermal history, before discussing how process parameters affect the weld properties riction stir welding, metal flow, process parameters, mechanical properties Issue-4 Volume-1 Danail Abdullah