On the Origin of Species to be expanded with his research results and published if he died prematurely. In November 1844, the anonymously published popular science book "Vestiges of the Natural History of Creation", written by Scottish journalist Robert Chambers, widened public interest in the concept of transmutation of species. "Vestiges" used evidence from the fossil record and embryology to support the claim that living things had progressed from the simple to the more complex over time. But it proposed a linear progression rather than the branching common descent theory behind Darwin's work in progress, and it ignored adaptation. Darwin read it soon after publication,
On the Origin of Species only the last chapter still to write. In September the main title still included ""An essay on the origin of species and varieties"", but Darwin now proposed dropping "varieties". With Murray's persuasion, the title was eventually agreed as "On the Origin of Species", with the title page adding "by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life". In this extended title (and elsewhere in the book) Darwin used the biological term ""races"" interchangeably with ""varieties"", meaning varieties within a species. He used the term broadly, and as well as discussions of "the several