This introductory article provides an overview of the historiography of scientific secrecy from J.D. Bernal and Robert Merton to this day. It reviews how historians and sociologists of science have explored the role of secrets in commercial and government-sponsored scientific research through the ages. Whether focusing on the medieval, early modern or modern periods, much of this historiography has conceptualized scientific secrets as valuable intellectual property that helps entrepreneurs and autocratic governments gain economic or military advantage over competitors. Following Georg (...) Simmel and Max Weber, this article offers an alternative interpretation of secrecy as a tool to organize and to hierarchically order society. In this view, the knowledge content of secrecy is less important than its social-psychological effects. The authors argue that, in many instances, entrepreneurial researchers and governments use scientific secrets as an effective tool to manipulate the beliefs of their competitors and the larger public, and not necessarily to protect the knowledge that they hold. (shrink)