This monograph is a highly technical analysis of the interaction of two phases in controlled experiments‎.‎ By using a perforated plate and stirred tank‎,‎ Dr Azbel has conducted experiments involving flow‎,‎ mass bubbling‎,‎ mass transfer during bubbling and in a liquid‎-solid system and the calculation of bubbling reactors for the two‎-phase oxidation reaction‎.‎ The last chapter investigates the design of a reactor for microbiological processes‎.‎ The behaviour of bubbles is a unifying theme of this book‎.‎ From an explanation of the fundamentals of bubbles formation at a single orifice‎,‎ Dr Azbel goes on to set up equations for bubble motion‎,‎ bubble size‎,‎ bubble‎-size distribution and pressure drop across a perforated plate‎.‎ His treatment of bubbles is expanded in later chapters to include mass transfer in the dispersion of solid particles in a liquid and mass transfer accompanied by chemical reactions in a bubble dispersion system‎.‎