These are requests to visit the laboratory: from scientists writing on their own behalf about research projects, or in a representative capacity on behalf of institutions or departments interested in laboratory organisation, teaching or research programmes; from government departments or embassies interested in setting up laboratories or in the workings of an international institution; from delegations or representatives of EMBL member states or elsewhere. Some of the exchanges are brief, others include information on proposed research and building plans on national and international levels, comments on EMBL organisation, letters of thanks and the like.