Development of bubble column reactor requires three types of reaction engineering basics, viz. kinetics of mass transfer and chemical reaction in gas-liquid heterogeneous system, flow dynamics of gas-liquid two phase system, and reactor modelling. Kinetic study includes not only various chemical reactions but also physical features such as photo irradiation, precipitate formation or biological processes. While bubble column flow has been extensively investigated for these three decades, much fundamental work could be a key to the further development. The synthesis of elemental behaviours of bubble column should be the most important part of the reactor development, although not so many examples are explored so far. These three topics are argued from the point of view of reactor design.