This is the first academic biography of the scientist and politician Jacob Moleschott (1822-1893). Based on a vast range of primary sources in German, Italian, Dutch, French, and Latin, it not only sheds new light on the history of materialism in the natural sciences, but also shows the deep entanglement of science, politics, and popularization in 19th-century Europe. Applying new methods from cultural history and the history of science, Laura Meneghello focuses on processes of knowledge circulation, transnational mobility, and the role of translation in 19th-century science.