Introduction.Nomenclature. The scope. Inert electrolytes. The significance of Parks' review. Structure of the adsorbents. Solubility. Solid phase transformation at room temperature in contact with solution. Solid phase transformation on heating. Kinetics. Solution chemistry ? pH scale. Very dilute solutions. Speciation in solution. Methods. Experimental setup in electrokinetic measurements. Experimental conditions in electrokinetic measurements. CO2 and silica problem. Experimental results - Electrokinetic potential. Experimental conditions ? titration. Results ? titration. Interrelation of results obtained by means of different methods. Other methods. Adsorption models. Compilation of PZC/IEP. Simple oxides. Aluminosilicates, phyllosilicates, clays and clay minerals. Mixed oxides. Salts. Glasses. Carbon and carbon-rich materials. Other inorganic materials. Coatings. Well-defined low-molecular organic compounds. Polymers (macroscopic specimens). Latexes. Natural high-molecular organic substances. Microorganisms. Metals. Literature intentionally ignored. Temperature effect. Pressure effect. Compilations of PZC of various materials. Correlations. Mixed water-organic solvents. Nonaqueous solvents. Conclusion. Ion specificity. Affinity series. Uptake of 1-1 electrolyte ions at or near PZC. High ionic strength. Appendix. Literature.