How does law protect in war? (the "Online Casebook") is an academic platform adapted from the original reference Casebook authored by Marco Sassòli, Antoine Bouvier and Anne Quintin, and published by the ICRC. It is intended to support teaching of international humanitarian law (IHL) in universities in an interactive way, and based on contemporary practice. The Law section features a general outline presenting IHL in 15 chapters. It contains comprehensive bibliographic resources and links each theme to a range of related case studies and documents. The Practice section comprises over 450 case studies and documents regrouped either by theme or by region, or by type of document. They allow practice-oriented learning of IHL rules and interactive discussions through series of questions. The Pedagogical Resources section provides useful advice on how to teach IHL, as well as 29 model course outlines and other useful resources. The A to Z section presents over 400 notions linked to IHL, their legal sources, the case studies where they are addressed, as well as bibliographic resources to delve further into those notions. A search engine allows users to find rapidly the relevant pedagogical material they need on the platform. In 2014, a first version of the online platform was launched. Do not hesitate to share thoughts and comments with the feedback button top right.