The International Astronomical Union (IAU) was founded in 1919. Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Its individual members — structured into Divisions, Commissions, and Working Groups — are professional astronomers from all over the world, at the Ph.D. level and beyond, who are active in professional research and education in astronomy. In addition, the IAU collaborates with various scientific organizations all over the world.

The key activity of the IAU is the organization of scientific meetings. Every year the IAU sponsors nine international IAU Symposia. The IAU Symposium Proceedings series is the flagship of the IAU publications. Every three years the IAU holds a General Assembly, which offers six IAU Symposia, some 25 Joint Discussions and Special Sessions, and individual business and scientific meetings of Divisions, Commissions, and Working Groups. The proceedings of Joint Discussions and Special Sessions are published in the Highlights of Astronomy series. The reports of the GA business meetings are published in the Transactions of the IAU - B series.

Among the other tasks of the IAU are the definition of fundamental astronomical and physical constants; unambiguous astronomical nomenclature; promotion of educational activities in astronomy; and informal discussions on the possibilities for future international large-scale facilities. Furthermore, the IAU serves as the internationally recognized authority for assigning designations to celestial bodies and surface features on them. The IAU also works to promote astronomical education, research and public outreach actions. 

Free access to the IAU archive