Since 1970 we know in Europe that, by engaging in intensive dialog and constructive cooperation it is possible to achieve a generally acceptable test procedure, despite the many divergent approaches taken by the different countries. When in 1966 I began my career as a microbiologist, different procedures were used in all countries to test the efficacy of disinfectants. The results of such tests did not at all lend themselves to comparison. One of the most important requirements to be addressed to a future, generally acceptable procedure was naturally that the results should be reproducible. To that effect, it was necessary to standardize all aspects of the test since even the slightest discrepancy could give rise to markedly different results. On the other hand, each specified detail had to be scientifically corroborated to prove acceptable to all parties. 1990 marked a major breakthrough towards harmonization of European disinfection test procedures with the founding of the "Chemical Disinfection and Antiseptics" (TC 216) working group within the framework of the "European Committee for Standardization (CEN). This served as a basis for Phase 1 (basic evaluation of the disinfectant effect or suspension tests under different conditions) and Phase 2 tests (tests on different surfaces under practice-oriented conditions). The quantitative principle is now valid for both phases. Major investments were needed to bring about European harmonization. We Dutch, in particular, are well known for having our own opinions. But we, too, continued to engage in discussions and collaborations until we reached a consensus and learned to respect each other and even to become friends in some cases. Today, harmonization endeavors extend well beyond Europe: with its biocide program, the OECD pesticides working group is working towards the development of a global test procedure for disinfectants. So we have not, by any means, reached the end of the road: there is still much to be accomplished by our successors: I am confident that we ...