Fantastic source of information on magic and witchcraft in Europe prior to and after Christianity was introduced. To be clear, this is a reader. Which means these are primary texts, by people living hundreds or even thousands of years ago.
Sadly, for a variety of reasons, there are very few primary texts about pre-Christian European religion written by actually pagan or heathen people. The overwhelming majority of the data comes from Christians who clearly didn't always depict things accurately. But Rampton has done her best to try to offer as much information, coming from different quarters, as possible, and this really is the most historically useful book I've come across on the subject.