Among historians of Reform Judaism, which emerged in Germany in the 1810s, which divided British religious Jews from the 1840s, and which came to dominate North American Jewry by the 1880s, there is a general absence of interest in Darwin’s theory of evolution. The idea of evolution more generally had been used by scholars of religion – and by leading Jewish reformers – to describe mankind’s religious progression from well before Darwin’s day. The father of German Reform Judaism, Abraham Geiger, presented the emergence of the modern forms of Judaism as an inevitable, evolutionary development from the 1830s; according to his view, history revealed how each generation of Jews had given fresh meaning to the traditional liturgy and practices that had sought to express the core ethical-monotheistic aspects of Judaism, leading to a perpetual state of organic change as the Jewish religion adapted itself to local circumstances and cultures. And similar arguments have been repeated ever since by progressive Jewish thinkers. But whereas Geiger made his argument without reference to biological evolution (in fact, he rejected not only Darwin’s theory natural selection but even the phenomenon of the transmutation of species itself),¹ many other Reform Jews preferred to make an explicit connection to biological evolution, especially in the U.S. While the language of evolutionism has not gone unnoticed by historians of Reform Judaism, the tendency has been to focus on the political ambitions of assimilationist lay Jews, the theological concerns of the religious leaders and intellectual pioneers of Reform, and the critique and emulation of the surrounding Christian societies in terms of theology and practices, all at the expense of the reformers’ actual engagement with evolutionary science.