Book excerpt: The International Meeting on Thermodiffusion provides a unique opportunity for sharing ideas about theoretical, experimental and numerical results on diffusion- and thermodiffusion related research. The successful series of IMT meetings aims to provide a forum for discussion, face-to-face interaction between scientists and technologists, and a mechanism for developing new collaborations. The IMT15 is aimed to discuss the latest results on transport properties in multicomponent fluids: innovative theoretical approaches, new experimental results and techniques as well as state of the art numerical methods. The most fundamental aspect of the conference will be the discussion amongst scientists, the sharing of ideas and creating new and reinforced existing collaborations.