'How should public debates be understood?' is the central question of this study. And it is answered by reconstructing a single public debate, namely the debate about the transgenic bull Herman. Herman the bull was created by Gene Pharming in 1989. An extra gene has been inserted in his genome as to induce the production of lactoferrin in the milk of his daughters. A debate started in the media about whether this should be allowed or not. This media debate has lasted for nine years. In this study the debate is analysed and interpreted in order to make visible for others what has happened during this particular debate. It thus provides handles for disclosing other public debates and for better understanding public debates in general.Insight is provided in what has kept this debate going. This media debate, in which the public is involved as an audience, has needed a concrete cause (the case) to develop. This seems to be obvious, but in the Netherlands many debates are being organised without such a case. And one may witness that the media, and so the public, are hardly involved in these organised debates. But not only will a case be needed to induce a public debate. The urge of the debate has to be articulated as well. Virtually everybody can articulate problematic aspects of a case, but for a debate to have impact actors are needed that can provide continuity to the debate. In this particular debate this continuity has been provided by the Dierenbescherming (the Dutch Society for the Protection of Animals). But, this still is not enough. If the media are not interested, the public will not know what is going on. So, for a vivid public debate, a case is needed to make the debate urgent, an organisation has to provide continuity, and the media have to publish about it.With respect to the content of the debate two discussions can be distinguished: a) the general controversy that has evoked the debate and b) the discussion about several specific applications of this technology.ad a) The general controversy. Four ...