This contribution reflects on the development of informal expert manuals in the field of the laws of armed conflict. These manuals are presented as restating existing customary law, perhaps adding a few elements de lege ferenda but not having a straightforward normative intent. The authors of expert manuals state them to be non-binding, and their drafting takes place mostly in self-appointed groups. Although a normative intent may be absent when drafting such informal expert manuals, such rules may obtain normative effect nevertheless. While States are mostly absent in these processes, they seem to have a specific interest in the development of these manuals.
