AbstractAt a meeting of the Association of British Geodesists held on the 5th April, 1965 at the rooms of the Royal Astronomical Society a discussion took place on Crustal Movements and their Measurement. This discussion was based on three short introductory papers specially prepared for the meeting. As it is thought that these papers and the resulting discussion may be of general interest to many readers, it has been decided to publish in these pages each paper in full and an account of the discussion which followed them.