In recent years, although having its origins earlier in the last century in electrochemistry of the double-layer and of H adsorption in the British and Russian literature by Rideal, Butler and Frumkin, and later Parsons, a recognizable subject of electrochemical surface science (ESS) has emerged. This field has advanced on account of development of electrochemical techniques having remarkably high sensitivities and specificities for following surface processes at electrodes, especially single-crystal surfaces, in contact with bulk electrolyte solutions. Such advances have placed ESS at the forefront of modem surface chemistry. This review illustrates this situation by presentation and discussion of some selected examples from the works of the present author and others where results pertaining to coverage by H, anions, surface-oxide films and organics are obtainable at high sensitivities, e.g. by means of linear sweep voltammetry, dc charging transients, coupled quartz-crystal nanogravimetry and in situ FTIR spectroscopy. Finally, the recent development and behaviour of so-called 'supercapacitors', based on double-layer capacitance at high-area C materials (2000 m(2) g(-1)), giving rise to capacitances of similar to50-100 F g(-1) of the C substrate, is described as an example of applied ESS.