The first section introduces the electrochemical nomenclature necessary for under standing the literature on ion-selective electrodes and discusses the general principles behind all electrodes. The second section is concerned with the problems which arise in any accurate elec trode potential measurement in practice. Here the most important reference electrodes are discussed with special reference to their use in conjunction with ion-selective elec trodes. From experience, almost 75% of all problems which arise when working with ion-selective electrodes are on account of the reference...