This collection of essays focusses on the following concepts: sovereignty (the unique, intangible and yet essential characteristic of states), statehood (what it means to be a state, and the process of acquiring or losing statehood) and state responsibility (the legal component of what being a state entails). The unifying theme is that they have always been and will in the future continue to form a crucial part of the foundations of public international law. While many publications focus on new actors in international law such as international organisations, individuals, companies, NGOs and even humanity as a whole, this book offers a timely, thought-provoking and innovative reappraisal of the core actors on the international stage: states. It includes reflections on the interactions between states and non-state actors and on how increasing participation by and recognition of the latter within international law has impacted upon the role and attributes of statehood.