Roux, J.-A. Keywords: Judicial assistance | International criminal law | Mots clefs: Assistance judiciaire | Droit pénal international | ABSTRACT J.-A. Roux devotes the course to the aid that States provide to each other in the fight against crime, that is to say, the support they lend themselves to fight the criminals who have disturbed the public peace in their territory. To do this, the author successively examines police aid, legal aid, and legislative aid. The author then raises the issue of the internationalization of aid and the unification of criminal law. J.-A. Roux consacre s…