Project MERIT is a special programme of international collaboration to Monitor Earth-Rotation and Intercompare the Techniques of observation and analysis. It was conceived in 1978 at IAU Symposium No 82 on Time and the Earth’s Rotation and a draft proposal was prepared by a working group set up by the Presidents of IAU Commissions 19 and 31. The proposal was endorsed at the IAU General Assembly at Montreal in 1979 August and at the IUGG General Assembly at Canberra in 1979 December, when the organisation and membership of the Working Group were modified accordingly. The Group is affiliated to the Commission on the International Coordination of Space Techniques for Geodesy and Geodynamics (CSTG), which is sponsored by the International Association of Geodesy (IAG) and by COSPAR. Project MERIT has received the support of the International Council of Scientific Unions and of many national organisations and observatories throughout the world.