Three decades of vulnerability research have generated a complex and growing body of knowledge.The concept of vulnerability,as well as its implementation in vulnerability assessments,is used in various disciplines and contexts.Correspondingly,a multitude of ideas and frameworks about how to conceptualize and measure vulnerability exists.To provide a structured representation of vulnerability,we have set up an ontology-based semantic wiki for reviewing and representing vulnerability assessments(www.vuwiki.org).Based on a survey of 55 vulnerability assessment studies,we first developed an ontology as an explicit reference system for describing vulnerability assessments.The ontology was then implemented in a semantic wiki which allows for the classification and annotation of vulnerability assessment.The resulting semantic wiki,Vu Wiki,does not aim at‘‘synthesizing’’a holistic and overarching model of vulnerability,but at(1)providing—both scientists and practitioners—with a uniform ontology as a reference system;(2)providing easy and structured access to the knowledge field of vulnerability assessments with the possibility for any user to retrieve assessments using specific research criteria;and(3)serving as a collaborative knowledge platform that allows for the active participation of those generating and using the knowledge represented in the vulnerability wiki.