Rev Prof Henry Drummond FRSE LLD FGS (17 August 1851 - 11 March 1897) was a Scottish evangelist, biologist, writer and lecturer. Many of his writings were too nicely adapted to the needs of his own day to justify the expectation that they would long survive it, but few men exercised more religious influence in their own generation, especially on young men. His sermon "The Greatest Thing in the World" remains popular in Christian circles. In 1877 he was lecturer on natural science in the Free Church College on Lynedoch Street in Glasgow, which enabled him to combine all the pursuits for which he felt a vocation. Drummond advocated for theistic evolution. His studies resulted in his writing Natural Law in the Spiritual World.