Just glancing over this thread again and it strikes me as absurd that certain scientific tracts are included but none that are geological in nature. Without the principles of uniformitarianism, stratigraphy, biostratigraphy etc. we would have never come to make use of the mineral and hydrocarbon wealth of our planet. to rectify this I submit the following:
James Hutton, Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe - the foundations of modern geology and the first real proposal of the idea of uniformatarianism "a geological doctrine. It states that current geologic processes, occurring at the same rates observed today, in the same manner, account for all of Earth's geological features" (google)
First geological map of an entire country, or 'The map that changed the world' William Smith - not a book I know but a seminal piece of work that included Smith's observation that fossils occurred in a specific order with layers of sedimentary rock. This is the first time rocks could be put in a recognised order based on the fossils they contained and is now known by the term biostratigraphy. It allowed redictions ot be made as to what might lie beneath the ground , simply based on observations at the surface. BEfore this landowners would dig on their estates in the hope of finding coal. After Smiths work it could be shows where the likely places were. A crucial development for industry and understanding the distribution of our natural resources.
Georges Cuvier, Mémoires sur les espèces d'éléphants vivants et fossiles - the first paper to establish a species of animal as extinct. Before this it was widely believed than extinction was impossible. Once extinction was accepted it revolutionised the way fossil remains could be studies and described, freeing scientists from attempting to fit fossil remains into existing groups, changing the way we viewed the past of our world forever.
Charles Lyell, Principles of Geology - the key document that argued for an Earth older than 6000 years, the age taken from Bishops Ushers work on the genealogies in the Bible. Refining and popularising Hutton's earlier theories it championed the idea that the slow processes at work today were responsible for all features visible from fossils to fjords. It required a planet that was far, far older than anyone had dreamed possible. It was a huge influence on Charles Darwin, who took it with him on the Beagle, and whose principle interest as a young scientist was geology.
Without these works the Origin of Species could not have been written. Geology established a view of the world within which the process of natural selection could operate. Most important was its evidence of a vastly ancient Earth, but also that rocks were organised and predictable and contained traces of strange and alien life forms that suggested ancient lineages stretching back far into the past. The idea of stratigraphy was later taken up by antiquarians and applied to their own investigative practices and modern archaeology was the result.
The Origin of Species was not doubt a world-changing book, but it is a shame the equally world-changing discoveries of geology that preceded it are so poorly understood or appreciated.