This introduction presents an overview of key concepts discussed in the subsequent chapters of this book. The book explores how experiences in Kosovo have changed the discourse of European security. It provides new and stimulating perspectives on how 'Kosovo' has shaped European post-post-Cold War reality. The book aims to contribute to the insecurity of the field of security studies by sidelining the theoretical worldview that underlies mainstream strategic thinking on the Kosovo events. It investigates how 'Kosovo' has developed into this principal paradigmatic sign in the complex text of European security. The book also investigates how its very marginality has emphasised the unravelling fringes and limits of the sovereign presence of what 'Europe' thinks it stands for, and how it affects the discourse on European security.