By the twentieth century, the Royal Society was an experienced publisher of scientific journals: the Philosophical Transactions had been founded in 1665, while the Proceedings was created in 1831. But the Society’s traditionally generous and gentlemanly approach to publishing had already become difficult to sustain by the 1890s. In this paper, I will investigate how the Society and its journals weathered the challenges of the twentieth century. These can largely be seen as deriving from the expansion of scientific research. During the first four decades, the key issues were editorial and financial: the rising number of papers being submitted meant more editorial labour to be done, and more paper, printing and illustrations to be paid for. After the Second World War, the new wave of journals issued by commercial publishers (e.g. Pergamon) brought worries about the ongoing role of society-publishing, as well as a possible new financial model for journal publishing. The Royal Society made certain changes in the 1960s which partially solved the editorial and reputational challenges facing its journals; but its clearest success lay in the notion of ‘self-help for learned journals’ (1963), which solved its financial problems for the medium term. These changes form part of the story of how scientific journals evolved from records of the research of gentlemanly scholars into the tools that make both knowledge and careers in the modern academic profession.