Revision with unchanged content. Independent SRI rating agencies are relatively new players in the socially responsible investment (SRI) market that have first emerged in the 1990s. Their presence can be seen as a result of the growing demand from institutional investors for independent research on corporate social responsibility. What are the historical roots of SRI and which factors have led to the emergence of this new business model? Robert Gehrcke introduces the reader to the subject by giving a presentation of the history and the current structure of the SRI market. The initial analysis is used to explain the emergence of independent SRI rating agencies and the vast variety of methodological approaches. One of them, Oekom’s Corporate Responsibility Rating, is presented in detail. An interview part with representatives from different SRI rating agencies goes deeper into current issues of transparency and standardisation of methodologies. The book is aimed at people with an interest in the SRI market in general and independent rating processes in particular. It provides useful analyses for institutions like unions, associations, NGOs and foundations which are associated with sustainable investment.