This chapter contains sections titled: The Critical Micelle Concentration (CMC) Micellar Structure and Shape Micellar Aggregation Numbers Factors Affecting the Value of the CMC in Aqueous Media Micellization in Aqueous Solution and Adsorption at the Aqueous Solution–Air or Aqueous Solution–Hydrocarbon Interface CMCs in Nonaqueous Media Equations for the CMC Based on Theoretical Considerations Thermodynamic Parameters of Micellization Mixed Micelle Formation in Mixtures of Two Surfactants References Problems