Within a decade, use of linked employer-employee data has enabled striking progress in our understanding of the functioning of the labour market as the arena where labour supply and demand interact, under the mediation of labour market institutions and regulations. This collection of papers illustrates the potential from use of linked employer-employee data. While the need for micro data has been identified, the discussion on the feasibility and conditions for granting wider access to these data by the scientific community is still evolving slowly. Ethical issues involved in accessing and analyzing micro data (such as confidentiality or restriction of data use to specific scientific projects) are a major concern of data producers and often turn into a source of miscommunication with the scientific community, impeding or delaying data access. Hopefully, the quality of the scientific results generated on linked employer-employee data and the respect for the ethical issues involved will prompt wider collection and dissemination of this type of data.