In the acquisition and selection process, the focus of the Library is on 15 main topics - the core of the Collection -, based on User statistics with regard to alerts and requests of the previous five years. These topics are:
- Public international law
- Customary international law
- Law of treaties
- Territory and jurisdiction
- Law of the sea
- International trade
- International organizations
- Human rights
- International criminal law
- International peace and security
- Settlement of international disputes
- International humanitarian law
- Private international law
- International law of procedure
- Municipal and comparative law