The Ascent of Man, a series of lectures originally given in Boston in 1893, presents Henry Drummond’s most controversial work. In these lectures, he explains the concept of evolution, the evidence in favor of it, and why the science behind it does not contradict Christian belief. Rather, Christianity and evolutionary theory agree, and both see humanity as collectively changing and progressing—intellectually and socially. Drummond rejects “the God of the gaps” theory, the belief that God can only be found in what human knowledge cannot explain, and argues that God is found in all creation. Similarly, he rejects mechanistic deism: the belief that God is no longer involved in the progressive outworking of creation. His work maintains both transcendence and immanence of God, with critical emphasis on historical Christian orthodoxy.