At a time when German philosophy was dominated by idealism, German philosopher and physician Ludwig Büchner (1824-99) wrote Kraft und Stoff, an influential work advocating materialism, in 1855. It went through many editions and was widely read across the world. The controversy surrounding the book led to Büchner leaving his post at the University of Tübingen, but he went on to establish the German Freethinkers' League, the first German organisation for atheists. This book, first published in 1864, is a translation of the eighth edition, and is edited by J. Frederick Collingwood, who wanted to bring Büchner's work to an English audience. It contains translations of the prefaces from the first, third and fourth editions of Kraft und Stoff, and an introductory letter from Büchner which expresses his belief that Darwin's theory of evolution has given support to his materialist theory.