We embarked on the adventure of researching IUPAC’s history a few years ago, inspired by the looming IUPAC 100 anniversary in 2019 and the desire of the French National Committee to host that year’s Congress and General Assembly in Paris. The proposal to host the fiftieth IUPAC General Assembly and forty-seventh Congress in Paris was received and approved by IUPAC Council during its assembly in 2013. Soon after, Jean-Pierre Vairon, a member of the organizing committee of the IUPAC 2019 Congress, contacted Danielle Fauque, and together we started to think about special symposia devoted to the history of IUPAC. At the Congress in 2015 in Busan, Korea, the idea was met with enthusiasm and interest from Natalia Tarasova, then president of the Union, and the project of this special issue was formed with Fabienne Meyers, Chemistry International editor. We also met with Christopher Brett later that year to speak about this project.