The International Commission on Mathematical Instruction (ICMI) was first established at the International Congress of Mathematicians held in Rome, in 1908, with Felix Klein as its first president, and in 1952 as an official commission of IMU. As a commission, ICMI is defined by two constituent components: the Executive Committee (EC) of ICMI, elected by the General Assembly of the International Mathematical Union (IMU) for a four-year term, and the ICMI Representatives of the member states, appointed by or on behalf of the Adhering Organization (typically, the national academy of science, the national mathematical society, or suchlike) or the National Committee for Mathematics (CM), also appointed by the Adhering Organization.
The members of ICMI are neither individuals nor organizations, agencies, etc., but countries. Member states are of two categories: all countries members of IMU are automatically members of ICMI and, in addition, ICMI may, with the approval of the Executive Committee of IMU, co-opt on an individual basis, as so-called non-IMU members, countries which for some reason or another are unable to join the IMU. There are currently 72 member states of ICMI. Each member state, whether an IMU country or not, is entitled to appoint a National Representative.
From the very beginning, the international journal L'Enseignement Mathématique, founded in 1899 by Henri Fehr and Charles Laisant, was adopted as the official organ of ICMI - which it is still today. ICMI also publishes, under the editorship of the Secretary, a Bulletin appearing twice a year. (Starting with Bulletin No. 39, December 1995, the ICMI Bulletin is accessible on the internet.)
As a scientific union, IMU is a member organization of the International Council of Scientific Unions, ICSU. This implies that ICMI, through IMU, is to abide to the ICSU statutes, one of which establishes the principle of non-discrimination. This principle affirms the right and freedom of scientists to associate in international scientific activities regardless of citizenship, religion, political stance, ethnic origin, sex, and suchlike. Apart from observing general IMU and ICSU rules and principles, ICMI works with a large degree of autonomy.