Abstract. The International Union of Geodesy and Geophysics (IUGG) began
anew after World War II with a new governance and membership structure. The
technologies developed during the war were brought to bear in the
extraordinary global scientific effort that was the International Geophysical
Year (1957–1958). Major changes in the geopolitical landscape have brought
about further changes in IUGG's structure. International scientific campaigns
encompassing multiple disciplines became commonplace, and international
scientific bodies were organized and networked. During this time period
(1940–1999), 15 general assemblies and 2 extraordinary general assemblies
were held, each in a different international venue. Summaries of each general
assembly are presented, as well as overviews of the changes in IUGG's
structure, finances, membership, and publications. The scientists, who led
the Union and contributed to the development of the Union, are also
presented.