Merck Manual Professional VersionThe Merck Manuals are the product of a collaboration between hundreds of medical experts worldwide, an independent editorial board of peer reviewers, and the Merck Manuals’ editorial staff of physicians and professional medical writers. For over 100 years, The Merck Manual has had complete editorial independence to present the best current thinking regarding medical diagnosis and treatment, and does not in any way promote or publicize Merck products. To ensure absence of commercial or corporate bias, authors and peer reviewers cannot be Merck employees, nor can they serve as speakers for Merck products, or in any other way represent the company (Merck, About Us)