The development of X-band klystrons at SLAC originated with the idea of building an X-band Linear Collider in the late 1980¡¦s. Since then much effort has been expended in developing a reliable X-band Power source capable of delivering >50 MW RF power in pulse widths >1.5 ƒÝs. I will report on some of the technical issues and design strategies which have led to the current SLAC klystron designs.