Origin of the Species

Origin of the Species is a decent size tome that primarily provides examples supporting Darwin's theory of natural selection. Most of the science now appears rather mundane. After all, this is commonly accepted now. Darwin does, come across as extremely cocky. It makes me wonder whether Darwin was given his credit because he was really smart, or just because he had the force to evangelize his positions. (Much of the work is filled with examples of other people's research.) In the conclusion, Darwin goes out on a limb and disparages anyone who disagrees with him, providing some of the arguments that are now common in any evolutionary debates.

Perhaps most ironically, however, is that he concedes that most of the species in existence could have been descended from five original species. (Hmmm... That almost sounds like a contemporary intelligent design argument.)
The book spends some time discussing the problems with the geological record. There are a great many holes in the geologic history due to the way organisms are preserved. The lack of certain fossils does not mean that the organisms did not exist. Without evidence, it is impossible to disprove long-term evolution through natural selection. (And it is also impossible to disprove evolution of species through other means.)
The book provides many examples supporting micro-evolution and the creation and plausible creation) of new beneficial features. He stresses that only new traits that provide a benefit to the individual organism will be propagated. (Though some traits could also provide benefit to others.) Creation of new species (and larger divisions) is primarily supported by supposition.

Darwin's pomposity is probably what gives him, rather than Wallace, the role of "evoution" standard bearer. While there is some decent scientific content in the book, the political rants are what have endured most.