IGUS is the International Group of Experts on the Explosion Risks of Unstable Substances. Today, the aim of the group is to exchange information on the behavior of unstable substances and to improve safety in production, storage, transport, and use of these substances. Full members of IGUS work for governments and independent research organizations. Experts from industry can and do attend meetings by invitation. IGUS's 50th anniversary in 2012 gives reason to have a closer look at the questions of how IGUS came to be, what IGUS's aims and objectives were, and how it is organized and working today.