This document discusses the value of grey literature to research, business, and society. It begins with an introduction to grey literature, providing examples and discussing issues around quality. It then discusses how annual global spending on research and development needs to be managed and justified. Examples are given of the impact of research from the UK. The value of grey literature is described as being behind almost all impact examples. However, obstacles need to be overcome to fully realize the value, such as difficulties finding and utilizing grey material due to lack of recording, access restrictions, poor metadata, and lack of classification. The document concludes by discussing policies around research publications.