*Resistive switching* refers to the physical phenomena where a dielectric suddenly changes its (two terminal) resistance under the action of a strong electric field or current. The change of resistance can be, both, non-volatile and volatile, and both, reversible and irreversible. Typical resistive switching cells are capacitor like devices, where the electrodes can be an active or inert metals and the dielectric, mostly, a transition metal oxide. The resistive switching device is one of the leading candidates to replace the current non-volatile memory (NOR and NAND Flash) based on the floating gate MOSFET transistor. The resistive switching effect is also at the base of the behavior of the so called memristor devices (postulated and described theoretically by Prof. Chua) and neuromorphic memories.