Introduction Rosa Luxemburg is best known for her attempt in her book The Accumulation of Capital (1913) to show that capitalist accumulation requires external markets in order to overcome a tendency to stagnation. These external markets formed the basis of her theory of imperialism, which was taken over by Lenin and subsequent Marxists. However, in Chapter 30 of that book, on ‘International Loans’, Rosa Luxemburg examined the role of finance in capital accumulation. This analysis was perhaps peripheral to her argument. But it has sufficient critical elements to warrant a place for Luxemburg among the pioneers of critical finance, while the fate of that analysis among Marxists reveals how the most important school of radical political economy in the twentieth century came to an attenuated view of finance as a factor in capitalist crisis. In this chapter, it is argued that Luxemburg put forward an analysis of international finance that not only allows for a disturbing character of finance, but also looks forward to important aspects of Minsky’s analysis in the second half of the twentieth century.