This edited collection builds directly upon the recently published book by Harmel, Svåsand, and Mjelde (Institutionalisation (and De-Institutionalisation) of Right-Wing Protest Parties: The Progress Parties in Denmark and Norway) and applies their conceptual framework to a wide range of additional cases. Employing a common conceptual framework throughout, the chapters cover a broad range of cases and make important contributions toward building theories on why some parties succeed in institutionalising while others fail. The book is primarily about the status some parties achieve as an ‘institution’, the means by which parties may acquire that status, and some of the obstacles that stand in their way.