On the Origin of Species was the first published book to propose natural selection as an explanation for evolution and the already established "mutability of species". It was written by naturalist Charles Darwin and published in 1859, about 20 years after his voyage on the HMS Beagle. While The Origin of Species is how the book is commonly referred to, the full title is On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races (Species) in the Struggle for Life. This book never mentions human evolution. By races, Darwin meant species. Darwin was not a racist, if he is compared to the Confederate-Christian white slave masters living in Alabama during the 1850s. The Ku Klux Klan would read a Bible verse from the twelfth chapter of Romans in Baptist churches.
Anyway, Darwin's first book states, "There are variations in creatures that are passed on to their descendants. Some of these variations are beneficial, and aid in the species' survival, and some are detrimental. The beneficial variations live on, and the detrimental ones die out." As well as numerous case studies and pieces of scientific evidence - and being shorter than Darwin actually intended - he spends several chapters countering concerns and criticisms offered by the many people Darwin discussed his theories with prior to publication.
Thomas Henry Huxley’s book, Evidence as to Man’s Place in Nature (1863) picked up where Darwin’s On the Origin of Species left off. Perhaps emboldened by Huxley’s efforts, Darwin produced his second-most important book, The Descent of Man (1871), which applied Darwin's theory to human evolution. Alfred Russel Wallace is a co-discoverer of natural selection and authored The Malay Archipelago (1869). Likewise, Friedrich Wöhler (1800–1882) revolutionized organic chemistry by creating the field of inorganic chemistry.
Herbert Spencer coined the term "survival of the fittest" in his Principles of Biology (1864) and this phrase was included in the fifth edition of Darwin's work. However, it has often been misinterpreted as "survival of the strongest" rather than "survival of the most fit for purpose" meaning the most adept at exploiting an ecological niche.
Many fundamentalist/evangelical religious people are highly offended by the concepts presented in Origin and the science of evolution that has developed since its publication. This is because it is obvious to them that it is easier to make people from dirt than from other living things.
“To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree. Nonetheless reason tells me, that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, ... then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable to our imagination, should not be considered subversive of the theory.”