This thematic dossier collects eight scientific papers corresponding to presentations made during two international conferences dedicated to the study of low permeability media held in Paris within six months of each other. The first conference, “The Challenge of Studying Low Permeability Materials: Laboratory, in situ (field) and numerical methods”, was organised in December 2014 by the University of Cergy-Pontoise (Geosciences and Environment Cergy Research Laboratory) under the aegis of CFMR (Rock Mechanics French Committee) and GIS Geosciences franciliennes. The second, LowPerm2015 “Low permeability media and nanoporous materials from characterisation to modeling: Can we do it better?”, was organised by IFP Energies nouvelles in June 2015 under the aegis of the French “Academie des Sciences”. An attractive and explicit title is key to the success of a conference. It sets the scene and lets possible participants know exactly what matter will be discussed. But subtitles may be as important as titles, because they may stimulate participants by confronting them with a collective challenge. Devoted to characterisation, transport properties and multiscale modeling of low to very low permeability media and nanoporous materials, LowPerm2015 was leaving very little ambiguity about the matter to be discussed. Its subtitle – Can we do better? – was a mild way of stressing that there are several areas where we should be totally unsatisfied about our present state of knowledge, and where progress is urgently needed. One of these areas is the recovery of unconventional hydrocarbon resources. There is no question that the gas and oil shale revolution has deeply changed the global energy landscape, but its long term sustainability is questionable in spite of the tremendous magnitude of the resource due to an unacceptably low rate of recovery. With close to seventy five percent of the gas and ninety five percent of the oil left in place on average, the exploitation of self-sourced organic rich shale reservoirs is one of the least efficient industrial operations. Among the main reasons for this are our poor knowledge of the complex nanoporous void space in which the hydrocarbons are trapped, and our very limited understanding of their release and transport mechanisms, particularly in multiphase conditions. Just imagine what the future would be if, thanks to improved understanding, we could switch from ninety five percent left in place to ninety five percent recovery!