The world of the expert is described in terms of consistency, pride and humility. When the expert moves out of this world, he can feel uneasy being neither a diplomat nor a communication specialist nor a negotiator. Communication can even prove difficult with other experts. Many situations are conflictual and the expert may not be trained to face such difficulties, let alone adequately briefed on the particular case at hand. In most difficult communication situations, uncertainty is the major area of concern.

Having thus framed the problems revolving around the communication of experts, the article describes efforts conducted under a European research project (EU FP6). The ERICA research project (Environmental Risks of Ionizing Contaminants: Management and Assessment) aims at building a software tool which will help evaluate radioecological risks. Relationships with end users and with other stakeholders have been specifically built into the project as Work Package 3. The End User Group initially included some 45 organizations: 20 expert organizations, 13 regulators, 6 international organizations, 4 citizens' organization and 2 organizations representing industry. This three year project is due to end by February 2007. Successful areas of communication within the project are briefly described as well as not so successful attempts.

We then investigate several possibilities for providing experts with tools and capabilities to tackle such problems. These include: training in public perception and the public's way of framing their concerns; collaborative tools which can facilitate exchanges between experts and their different types of public; knowledge management tools allowing different presentations of ideas. We believe that ensuring communication between experts and their public should be defined as a job in its own right. A job which takes two fairly different aspects: explaining what the experts do and know to the public, on the one hand; and, on the other hand, bringing the public's conceptions and concerns to the attention of experts, in general, and of the right expert in particular.