We all know that Charles Darwin arrived at the great synthesis of evolution working alone in the seclusion of Down House (yet even he encountered some publication problems!) and that Albert Einstein also worked in isolation in the Patent Office in Bern. Scientists working alone can continue to make great discoveries, but in the past half century the nature of much of scientific research has undergone major changes. These changes are partly due to the tremendous expansion of the research community and institutions, which in former times consisted of a handful of individuals, but have increased in size by one or more orders of magnitude.