The Introduction to the first Volume gives a brief “State of the Art”, a Status Quaestionis, of how the term “vulnerability” has evolved and become a common category in many disciplines, in the last 50 years. It also raises the fundamental questions that have been in the background of this research throughout the course of its development. It establishes that despite its profuse development, theorizing its basic content has been as diverse as it is extensive, and today its definition is considered both necessary and controversial.