On 20 April 2015, Professor Nikola Kallay passed away in his sleep, leaving a huge gap in his family, among his friends and colleagues, and in the chemical community as a whole.
He was a Titular Member of Commission I.1 from 1977 to 1985, Associate Member until 1989, and initiator of the project on the revision of the IUPAC Green Book which lead to its first edition in 1988, second edition in 1993, and third edition in 2007. Those of us who worked with him will remember the many discussions and fierce arguments we had as well as the charm with which he introduced “jokers” for each one of us, writing the text by which a particular formulation could be passed even if we were unable to reach a unanimous agreement on it.

The Working Party on the revision of the Green Book in Dubrovnik, Croatia, March 1986: from left Tom Cvitaš, Klaus Homann, Ian Mills, Kozo Kuchitsu and Niki Kallay.
©2015 by Walter de Gruyter Berlin/Boston