If you are interested in the research of magic and witchcraft in the middle ages you may have come across the following seminal works:

Henry Charles Lea‘s A History of the Inquisition (3 volumes): although this title covers all of the activities of the inquisition and therefore mainly the crime of heresy, there is also some useful content on how the inquisition tackled magic and witchcraft (see volume 3 for this).

Lynn Thorndike‘s A History of Magic and Experimental Science: this title contains 8 volumes, the first two of which cover the first thirteen centuries A.D. The book lists all the major developments in magic and experimental science and also provides details of known ‘magicians’ during that time period. Scientists such as Roger Bacon were often thought to be magicians because of the unusual claims that they made and the experiments they carried out.

In the past it has been quite difficult to get hold of these important reference books unless you have access to a well-stocked academic or public library. I briefly had access to A History of the Inquisition via a trial subscription to Questia, but that has since lapsed. But now the good news is that both titles are available via archive.org. You can find all three volumes of A History of the Inquisition of the Middle Ages, as well as the same author’s A History of the Inquisition of Spain. For Thorndike you can find the first two volumes at present. Hopefully the other volumes will be added soon as well.

Simply visit archive.org and start your search. There are often multiple files available, so I won’t provide any links here. If you have never used archive.org before then please take a look, it’s a great resource.