This article takes Pieter Kooijmans’ 1964 book as the launching point for a discussion of contemporary issues relating to the legal equality of States in the context of immunity from suit. It assesses the strengths of the ‘Grundnorm’ of sovereign equality and examines whether it has any real role to play in providing answers to current problems, including whether immunity should be set aside in the face of claims that a foreign State or its agent has committed human rights violations. Close attention is paid to the 2012 Judgment of the International Court of Justice in the Jurisdictional Immunities of the State case. That Judgment demonstrates that sovereign equality has not yet been replaced as the generating principle of law in the realm of immunity. At the same time, there is an emerging alternative approach centered on the individual rather than the State.