The government’s Research Excellence Framework (REF), which determines the allocation of research funding to British universities, tends to reward microadvances in each field. These usually take the form of articles published in the top peer-reviewed journals, particularly in the USA. This suits some disciplines better than others. When I was director of the London School of Economics, the historians there often complained that long books summarising big themes for a general audience became rarer as a result. They had a point.