The monograph is devoted to the description of the kinetics of spontaneous boiling of superheated liquefied gases and their solutions. Experimental results are given on the temperature of accessible superheating, the limits of tensile strength of liquids due to processes of cavitation and the rates of nucleation of classical and quantum liquids. The kinetics of evolution of the gas phase is studied in detail for solutions of cryogenic liquids and gas-saturated fluids. The properties of the critical clusters (bubbles of critical sizes) of the newly evolving gas phase are analyzed for initial states near the equilibrium coexistence curves of liquid and gas, for states near the limits of accessible superheating and for initial states near the respective spinodal curves. Finally, processes of explosive boiling of cryogenic liquids are considered occurring as the result of outflow processes and intensive interactions with high-temperature liquid samples.