This book is the first academic monograph to provide a critical analysis of the WTO’s Trade Policy Review Mechanism (TPRM). In order to do so, it first looks at the TPRM’s historical development into the WTO’s mechanism for peer review. In this context, the book provides a historical analysis of the concept of peer review and distils a peer review mechanism’s theoretical core elements in terms of objectives, structure and participants. It then applies these elements to the five defining institutional phases of the TPRM (Article X of the GATT (1947), the Tokyo Round negotiations resulting in the Understanding Regarding Notification, Consultation, Dispute Settlement and Surveillance (1979), the report ‘Trade Policies for a Better Future: Proposals for Action’ (1985), the Functioning of the GATT System (FOGS) negotiations (1986), and the provisional adaption of the TPRM during the Montreal mid-term review of the Uruguay Round (December 1988)). The book then measures to which degree the TPRM has been performing well as the WTO’s mechanism for peer review. In order to do so, it follows the first five institutionally mandated appraisals of the TPRM (1999, 2005, 2008, 2011, and 2013). The book concludes that the TPRM has functioned well but that its performance could and should be improved in order to remain politically relevant. In order to do so, it provides some recommendations which are tested against the background of the last (sixth) appraisal which precede the upcoming Eleventh WTO Ministerial Conference in Buenos Aires (December 2017).