Travaux Préparatoires = "[French 'preparatory work'] Materials used in preparing the ultimate form of an agreement or statute, and especially of international treaty; the draft or legislative history of a treaty." Black's Law Dictionary (9th ed. 2009).
For further understanding of treaty interpretation and the use of travaux préparatoires, see:
Jonathan Pratter, À la Recherche des Travaux Préparatoires: An Approach to Researching the Drafting History of International Agreements, GlobaLex (July 2017).
Martin Ris, Treaty Interpretation and ICJ Recourse to Travaux Préparatoires: Towards a Proposed Amendment of Articles 31 and 32 of the Vienna Convention on the Law of Treaties, 14 B.C. Int'l & Comp. L. Rev. 111 (1991).
Travaux Préparatoires, often referred to as travaux, are an important source when interpreting treaties because they can help elucidate the drafters' intent. Consulting travaux is an essential research step when treaty interpretation is at issue.
A list of travaux available at Pace Law Library related to criminal law and beyond. Click here for more titles.
The Genocide Convention by 
Guide to the "Travaux Preparatoires" of the International Covenant on Civil and Political Rights by 
The Implementation of International Humanitarian Law by 
The International Criminal Court by 
The International Criminal Tribunal for Rwanda by 
The Slavery Conventions by 
The Travaux Prèparatoires of the Crime of Aggression by