With a title like "Ghosts: A Natural History" I was expecting something more cohesive, with a throughgoing historical narrative and perhaps a methodical tracing of historical societal trends affecting or affected by supernatural beliefs or events. Some parts of this book seemed to be trying for that, sort of, but the final product is just kind of all over the place.
The first two chapters consist of a personal introduction wherein the author describes his own experiences with alleged hauntings, thus explaining his interest and motivation for writing the book, and then a taxonomy of different types of ghosts, which would seem like a setup for how the rest of the book will be structured, but it's not; it is, in fact, almost never referred to again. The remaining chapters describe various alleged supernatural events, arranged in (very loose) chronological order, from the 17th to the mid-20th century. It should also be noted, the focus of the book is almost exclusively British; I didn't mind that, but it would have been nice to know going in (especially since the cover copy explicitly mentions American figures like Ben Franklin -- he only actually shows up in a couple end notes.)
The early chapters reminded me very strongly of those little paperback collections of "true" ghost stories I used to get as a kid from school book fairs (and in fact I actually remember reading about a couple of the hauntings mentioned here in those books), where a single haunting is described from beginning to end, but this discrete style is abandoned in later chapters for briefly describing several examples of thematically (loosely) connected incidents. The tone in discussing the older episodes seems curiously credulous, even when describing events the author later explicitly calls out as hoaxes, while some of the later chapters come off almost as a dedicated skeptical takedown, with only laughably weak "but maybe" lines left for doubters*. The overall writing style is rambling and unfocused, with some chapters seeming to forget where they started by the end. The end notes are an utter mess; a few of them are actual, important information that should have been included in the body of the text, some are interesting asides for the curious, and several are completely irrelevant non-sequiturs that should have been left out entirely.
And speaking of non-sequiturs, the sheer number of times this guy points out obviously benign and even expected coincidences like they're something eerie or significant is maddening. This happens with several details, but it's especially glaring when, for example, he's pointing out family connections among the British aristocracy. They're ALL related to each other! It is not significant that Lady So-and-So who saw this ghost is the great niece's stepbrother's third cousin twice removed of Lord What's-His-Name who saw this other ghost a hundred years before. That's just what happens when you have a small, insular group of people who all keep marrying each other for hundreds of years.
Overall, I wanted to like this book. I was looking for an actual history, but even if it had just been a competently edited collection of "true" ghost stories, I probably would have been decently satisfied. But it couldn't decide what it wanted to be, and it ended up just a boring, jumbled mess.
*For the record, I'm a skeptic, so I'm not necessarily saying he's being unfair, but it is a notably inconsistent tone.