Most of the main epistemological principles and notions which govern the professional practice of journalism are not explicitly stated but implicitly presupposed. Stylebooks are a paradigmatic case of how these ideas are subtly, but firmly, embedded in the newsmaking process. Although these works appear to be “merely” grammar and stylistic handbooks, they actually are much more than that: they bear on issues related to professional judgement, that is to say, on underlying criteria which are the basis of journalistic work.