Concepts are one of the main material of international politics, yet, often is the task to study them left to historians and political theorists. In order to correct that, the Workshop “Concepts at Work” (Jerusalem, 31.5-1.6.) intends to broaden the picture. Organized by Piki Ish Shalom from the Hebrew University of Jerusalem a rich set of studies on concepts such as self-determination, international community risk, sovereignty, or homeland will be discussed. At the workshop I will present a first sketch on the life of the concept of blue economy and how it has shifted meaning over the past 5 years. The workshop program is available here.