The annular centrifugal contactors based on the Taylor-vortex flow have a great potential in chemical, nuclear, metallurgy and biotechnology industry. This equipment has been extensively studied during the past 80 years. However, most of the research has been focused on the flow instabilities. Relatively scanty information is available on the detailed quantitative flow pattern in single and multiphase flows, mixing and axial mixing, mass and heat transfer coefficients, drop and bubble size distribution, and so on. The published literature on these aspects has been critically analysed and presented in a coherent manner. Recommendations have been made for correlations which can be used for design purpose; lacunae in the available literature have been delineated and specific recommendations have been made for further work.