Gas flows in microsystems are of great interest for various applications that touch almost every industrial field. This diversity is typified through the following examples: fluidic microactuators for active control of aerodynamic flows, vacuum generators for extracting biological samples, mass flow and temperature micro-sensors, pressure gauges, micro heat-exchangers for the cooling of electronic components or for chemical applications, micropumps and microsystems for mixing or separation for local gas analysis, mass spectrometers, vacuum and dosing valves. The main characteristic of gas microflows is their rarefaction, the level of which often requires a modelling both by continuous and molecular approaches. The role played by the interaction between the gas and the wall becomes essential and is generally badly known. Numerous models of boundary conditions are currently in confrontation and require an empirical adjustment strongly dependent on the micro manufacturing techniques. On the other hand, the experimental data are fragmentary and difficult to confront. Most of them do not address heat transfer and gas mixtures issues. The proposed network has been built from several existing collaborations within bilateral programmes, from scientific collaborations and national networks. However, there was no global coordination of the research efforts in the field of gas microflows at the European level. Thus, the two primary objectives of this ITN project are: (i) to structure research in Europe in the field of micro gas flows to improve global fundamental knowledge and enable technological applications to an industrial and commercial level; (ii) to train ESR and ER at a pan-European level, with the aim to providing both a global overview on problems linked to gas flow and heat transfer in microsystems, and advanced skills in specific domains of this research field.