Resumen
While the Private Finance Initiative (PFI) is doubtless the most visible Public-Private Partnership (PPP) in the public debate it is by no means the only one. A number of scholars have outlined the ambiguity of the PPP concept beyond PFIs and pointed to the multiplicity of differing types and understandings. Thus, when examining up close, the PPP concept seems to cover a jungle of arrangements and settings. However, induc-tive explorations across disciplinary and professional borders are still scarce. This ar-ticle addresses this lack and reviews more than 100 publications for their PPP concepts and classifications. Following, the article first of all identifies the emergence of two dimensions that are differently emphasized by the proposed PPP definitions (1) the co-responsibility dimension and (2) the relational governance dimension. Second, the arti-cle finds two differing approaches within each dimension being the interventionist and marketization approach within the co-responsibility dimension and the structural and managerial approach in the relational governance dimension. Third, the reviewed vari-ety of classifications illustrates the infinitive number of criteria that can be used to order the within-concept variety. Thus, while the developed map in this article highlights some (re)occurring and uniting patterns it also points to the inevitable ambiguity of the PPP concept and consequently encourages scholars to stay precise and keep on mapping.