“Natural Law in the Spiritual World” is a 1883 work by Scottish writer and evangelist Henry Drummond. Within it, Drummond explores the connections between the world of religion and spirituality, and the physical world. He maintains that the ostensible dichotomy between the spiritual and the physical is in fact illusory, and that faith is actually aligned with science. Published only a few decades subsequent to Darwin’s landmark “On the Origin of Species”, Drummond’s attempt to reconcile evolution and God constitutes one of the most significant books related to Christian faith and scientific progress. Contents include: “Religion”, “Analysis of Introduction”, “Biogenesis”, “Degeneration”, “Growth”, “Death”, “Mortification”, “Eternal Life”, “Environment”, “Conformity to Type”, “Semi-parasitism”, “Parasitism”, “Classification”, etc. Rev Prof Henry Drummond (1851–1897) was a Scottish biologist, evangelist, lecturer, and writer. He had a considerable religious influence on his own generation, and his sermon ‘The Greatest Thing in the World’ is still popular within Christian circles. Other notable works by this author include: “Natural Law in the Spiritual World” (1883), “Tropical Africa” (1888), and “The Greatest Thing in the World: an Address” (1890). Many vintage books such as this are becoming increasingly scarce and expensive. It is with this in mind that we are republishing this volume now in an affordable, modern, high-quality edition complete with an essay on religion by James Young Simpson.