Money is everywhere in science. Yet, historians have only rarely placed the money trail at the centre of their analyses. The articles in this focus section demonstrate that following the money offers a historiographical path for investigating a number of key issues across disciplinary boundaries in the nineteenth and twentieth centuries. Drawing on cases and materials relating to a number of scientific fields including electrical engineering, aeronautics, agriculture and palaeontology, the articles examine the continuous role of money in industrial and military patronage, personal connections and networks, spatial and geographical dimensions of science as well as in relation to state funding and ownership. Together, the contributions demonstrate how following the money offers a way of overcoming hyperprofessionalism in the history of science.