Small parameters were introduced for describing the kinetics of aggregation of nonionic surfactants in solutions in an analytical form. The direct and reverse transition of molecular aggregates over the activation barrier of aggregation at a surfactant concentration between the first and second critical micellation concentrations was described. The kinetics of the initial stages of micellation was considered. Expressions for the characteristic times of attainment of the quasi-equilibrium concentrations of molecular aggregates in the micellar, subcritical, and supercritical regions, as well as the time of attainment of the quasistationary concentration of molecular aggregates in the near-critical size region were derived. The times of rapid and slow relaxation of the solution were examined. The total time it takes to establish the state of complete equilibrium in the solution was determined. It was demonstrated that this time decreases with increasing concentration of micelles. A probabilistic-statistical interpretation of the mean time interval between two consecutive emissions of a surfactant monomer from a micelle, the mean life time of a surfactant monomer in the micelle, and the mean lifetime of a micelle was proposed. The hierarchy of characteristics times of aggregation in micellar solutions, which characterize a complex multistage character of the nucleation and decomposition of micelles and the establishment of equilibrium in micellar solutions, was discussed. It was demonstrated that these hierarchy arise due to the existence of small parameters in the kinetic theory of aggregation.