My collection of non-fiction fits into several categories, with clear lines between some of them, and blurry lines between others. These pages look at some of those categories.

• Earth Science includes books about geology and related topics: volcanoes, earthquakes, plate tectonics. It also includes books about fossils and ancient life: dinosaurs, ancient mammals, paleoanthropolgy, and the whole history of life on Earth.
• My Life Science category includes books that talk about modern-day wildlife: cats and related animals, dogs and their relatives, ocean life, and ecology. The line between fossil life and modern life is one of those blurry ones I mentioned, so some of these books also talk about fossil relatives of living animals too. There's also a page here of field guides to birds, animals, plants, and other subjects.
• Related to both of the above categories is the area of Evolutionary Theory. Here you'll find books about Charles Darwin and his original theory of evolution, along with books about the theory in general, and books written by other specific authors such as Richard Dawkins and Stephen Jay Gould about many aspects of the theory.
• My other major non-fiction interest is History. Here you'll find books about archaeology, as well as a large collection of books about warfare and armies through the ages, with special focuses on the American Civil War and World War II.
• Finally,my Miscellaneous category includes the books that don't fit anywhere else. One shelf holds nonfiction books by Isaac Asimov, whose interests were even more eclectic than mine. Another shelf is full of books about space exploration. You'll also find books about shoips and sailing, and books about modern military technology, and finally a few books about pseudoscience -- Atlantis, conspiracy theories, and other such nonsense.