The Cochrane Reviews in the Cochrane Database of Systematic Reviews are prepared by authors who register titles with one of 52 Cochrane Review Groups. Each Cochrane Review Group focuses on a specific topic area and is led by a Coordinating Editor(s) and an editorial team including a Managing Editor and an Information Specialist. The Cochrane Review Groups provide authors with methodological and editorial support to prepare Cochrane Reviews, and manage the editorial process, including peer review. These systematic reviews differ from other types of review in that they adhere to a strict design in order to make them more comprehensive, minimizing the chance of bias, and ensuring reliability. Rather than reflecting the views of the authors, or being based on a partial selection of the literature, (as is the case with many articles and reviews that are not explicitly systematic), they contain all known references to trials on a particular intervention and a comprehensive summary of the available evidence.