"Lastly, will you be so very kind as to look at the enclosed title and give me your opinion..."¹ So wrote Charles Robert Darwin to friend and fellow scientist Charles Lyell in March 1859. The "title" Darwin referred to is that for his soon to be published On the Origin of Species by Means of Natural Selection, a book which provided a scientific explanation or theory of how species change through time. Without question a watershed work in the history of modern life sciences, Darwin's Origin elaborated a proposition that species slowly evolve from common ancestors through the mechanism of natural selection. As he himself expected, Darwin's theory became, and continues to be in some circles, the object of intense controversy.

Darwin had actually completed the research that resulted in On the Origin of Species some twenty years before its publication in November 1859. Very soon after completing his studies at Christ's College, Cambridge, Darwin obtained the position of naturalist on the 1831-1836 round-the-world scientific expedition of the H.M.S. Beagle. His notes and specimens taken on this circumnavigation of the Southern Hemisphere provided the raw data to argue for the evolution of species slowly through time.

Interestingly, as Michael Ruse has written of his education, "[b]y the time his Cambridge career had ended in 1831, Darwin was hardly a professional scientist -- or a professional anything. But for three years he had mixed with some of the leading scientists of his day, at a level far more intimate than would be possible for an undergraduate today."² Through close contact with the likes of John Stevens Henslow, Adam Sedgwick, and William Whewell, Darwin pursued his deep interest in the study of the natural world.

When he shipped-out aboard the Beagle, Darwin took with him a copy of Lyell's first volume of the Principles of Geology (1830). Accepting Lyell's gradualist notion of geological change, Darwin began to look at the world around him, both animate and inanimate, in similar terms. Lyell and Darwin met soon after the return of the Beagle to England, and they soon became close friends, although Lyell would never fully accept Darwin's theory of evolution.