Henry Drummond was a talented natural scientist with a powerful faith. His combination of talents led to the scientific and spiritual musings that resulted in Natural Law in the Spiritual World. In the preface of Natural Law, Drummond states that, “No class of works is received with more suspicion. . . . than those which deal with science and religion,” yet he felt called to expound upon what he saw: namely that natural law and spiritual law were not separate from one another. As predicted, his work sparked a great deal of interest, commentary, and criticism among nineteenth-century scientists and theologians. Many, while generally approving, felt called to expand upon the conversation Drummond started, while others argued against it or expressed concern on its theological impact.