The Cochrane Library is a collection of six databases that contain different types of high-quality, independent evidence to inform healthcare decision-making, and a seventh database that provides information about groups in The Cochrane Collaboration. The Cochrane Database of Systematic Reviews (CDSR) contains protocols and reviews of interventions, diagnostic tests, and methodology. The Database of Abstracts of Reviews of Effects (DARE) covers a broad range of health related interventions and thousands of abstracts of reviews in fields as diverse as diagnostic tests, public health, health promotion, pharmacology, surgery, psychology, and the organization and delivery of health care. The Cochrane Central Register of Controlled Trials (CENTRAL) brings together abstracts of published articles from EMBASE, MEDLINE, and other published and unpublished sources. The Cochrane Methodology Register (CMR) is a bibliography of publications that report on methods used in the conduct of controlled trials. The Health Technology Assessment (HTA) database brings together details of completed and ongoing health technology assessments (studies of the medical, social, ethical, and economic implications of healthcare interventions) from around the world. The NHS Economic Evaluation Database (EED) contains information about both costs and effects that are essential to making evidence-based decisions about competing healthcare interventions throughout the world. (Updates: CDSR, CENTRAL, and About are updated monthly. DARE, CMR, HTA & EED are published quarterly.)