This book contains the Introduction to the Open University course S250: Science in Context and also Topic 1 BSE/vCJD. The Introduction to the course provides brief synopses of the seven topics that form the core of S250. It also introduces the four themes - communication, risk, ethical issues and decision making - that permeate these topics. Topic 1 BSE/vCJD documents the key scientific and societal developments that surrounded the emergence of the cattle disease BSE (bovine spongiform encephalopathy) and the detection of the fatal human brain disease, vCJD (variant Creutzfeldt-Jakob disease). Arguably, the management of these two linked diseases has influenced many people's perceptions of new developments in science and of reassurances concerning safety offered by politicians and experts.