"Systematic reviews summarise primary research. They are central to the evidence- based medicine movement and are widely acknowledged as the best form of evidence on which to base healthcare decisions. The Cochrane Collaboration exists to produce systematic reviews of healthcare treatments. To be reliable, systematic reviews should be conducted to the highest level of scientific rigour. This book enables Cochrane and other systematic review authors to do this and to ensure their review is of the highest quality and avoid methodological pitfalls"--