Mass transfer involves the use of various operations to separate a mixture into its individual components—a frequent requirement in chemical industries. The differences in the physical properties of the components to be separated – such as the vapour pressure, solubility or diffusivity – are utilised to transfer material from one homogenous phase to another. Techniques such as gas absorption, distillation, leaching, extraction, crystallisation, humidification, drying, adsorption and membrane based separation processes involve mass transfer and can be carried out due to the existence of a concentration gradient within the system. Mass Transfer Concepts equips an engineer with knowledge of all these operations.