New in paperback. Hardcover was published in 2022. Organised around five key themes, this handbook offers an authoritative 'encyclopaedia' of differentiation and addresses questions such as: How can one define differentiation in the European Union in the light of the most recent events?; Does differentiation create more challenges or opportunities for the European Union?; Is Europe moving away from an 'ever closer Union' and heading towards an 'ever more differentiated Union', especially as leading political figures across Europe favour the use of differentiation to reconcile divergences between member states?