There is currently great interest in finding new ways for in situ control of structure and dynamical properties of materials at the micro and nanoscales. One of the most attractive routes is to use variation of applied voltage, an approach shared by a wide spectrum of disciplines including nano- and microfluidics, optofluidics, nanotribology, microrobotics, and tunable optical metamaterials. With portable applications and energy saving demands in mind, the most promising scenarios are related to ultra-low voltage control. The latter is generally achievable under electrochemical conditions which require involvement of electrolytic components and electrical double layer effects at the nanoscale. This Faraday Discussion brings together internationally leading researchers in this new interdisciplinary field to explore ideas on the physical and chemical principles underlying these phenomena. The book covers electroactuation effect, voltage controlled friction, electrotunable wetting, and the tuning of surface plasmons in nanostructures - bringing communities together in this interdisciplinary field.