Eternal Life is a fascinating religious philosophy book by Henry Drummond that deals with the subject of future life. Henry Drummond FRSE FGS (17 August 1851 - 11 March 1897) was a Scottish evangelist, biologist, writer and lecturer. Many of his writings were too adapted to the needs of his own day to justify the expectation that they would long survive it. 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, the argument being that the scientific principle of continuity extends from the physical world to the spiritual. Before the book was published in 1883, an invitation from the African Lakes Company took Drummond to Central Africa.