This special topic volume captures a snapshot of the last research results of mass and thermal transfer processes in materials and engineering systems currently under extensive investigation worldwide. The breadth of utilization of the mass and thermal transfer processes in engineering is reflected in the correspondingly wide range of topics covered here. Topics range from the research in atomic-scale right up to the macro scale, from basic research on properties right through to actual engineering applications, from hydrogen diffusion in a Pd-Cu alloy membrane to investigating the water-oil separation process.