Previous studies have revealed the existence of illegitimate authorship, e.g. gift authors and ghostwriters, in Scandinavian journals as well as in international high-impact medical journals. In order to obtain transparent and accountable research it is important to eliminate inappropriate authorships, and in this review, we argue, this could be done by extending the knowledge of the authorship criteria and the different types of illegitimate authorship, especially through the education of both students and doctors.