Written in response to this question:

I’m sure you get asked this every day but what are some good books to learn about werewolves? Like.. historically and where the legends came from and stuff. Always wanted to learn about them and vampires! So I guess vamp recs would be nice too… Thank you!

I don’t get asked this often, actually – so thank you for your interest! Always happy to help others find sources.

My favorite books on werewolves are:

  • A Lycanthropy Reader: Werewolves in Western Culture by Charlotte F. Otten – This is a wonderful collection of primary sources when it comes to werewolf legends (even if I don’t like Bernice Housman’s The Werewolf and think it has no place in this book). Otten also provides us with interesting and useful information about each source, as well as her own musings on werewolves and her experiences studying them. Absolutely worth a buy and a good several reads. I’ve used this book for my entire career and well before it in my childhood.
    • A previous review I wrote on it, for academic purposes: Perhaps the single most useful and best-written work on werewolf legends, Otten has compiled an excellent reader of many works on lycanthropy that anyone in the field should own. She also includes an excellent introduction. Unquestionably a must-have, even to those only interested in lycanthropy as fans of werewolf media.
  • The Werewolf in Lore and Legend by Montague Summers – Also sometimes published as just Werewolf or The Werewolf; my favorite printing of it is published under Werewolf, by Martino Publishing. This is a book that is very extensively researched, by the English author and clergyman Montague Summers, who dedicated his life to researching witchcraft, vampires, werewolves, the undead, and a lot more. This is an extremely extensive and useful book that comments on many other sources (be sure to read it alongside my next recommendation, as I love many of Summers’s comments on Baring-Gould’s work and the flaws therein). Read this carefully, though, as it is a very biased source; Summers believed in all of these things and that they are work of Satan and must be purged from the world. That doesn’t make his dedication to compiling and translating sources any less incredible, and he has many useful sourcebooks, all of which I’m happy to say I own (including his wonderful translation of the Malleus Maleficarum).
    • A previous review I wrote on it, for academic purposes: A must-have for anyone in the field. Summers is perhaps more extensive in providing useful information on werewolves and werewolf legends even than Baring-Gould, instead of focusing on madmen – however, he always discusses werewolves with his bias that they are real and are related to Satan.
  • The Book of Werewolves: Being an Account of a Terrible Superstition by Sabine Baring-Gould – Also sometimes published simply as The Book of Werewolves. Sabine Baring-Gould set out researching werewolves before Summers, and with a very different purpose: to prove they could be rationally explained and never truly existed. So, likewise, he is a very biased source, always feeling a need to clarify his research into folklore with “but this can’t be real and here is why” ad nauseum instead of continuing to simply present the information. However, he has written a concise and useful book, even if he does not translate all of the passages (bring some Latin, Old English, Old Norse, and French experience, at the very least), and even if he has an annoying focus on insanity and serial killers, as many werewolf scholars do. But he still has lots of very good and well-researched information all in one convenient place.
    • A previous review I wrote on it, for academic purposes: Although undeniably one of the most-used and most useful sources for werewolf folklore and history, Baring-Gould nonetheless includes a considerable amount of strange and overall irrelevant information, particularly where madmen are concerned, and frequently shows his bias. Regardless, this is a must-have for anyone in the field. 
  • The White Devil: The Werewolf in European Culture, by Matthew Beresford – This is a very good book, even if some of it is odd and feels somewhat out of place. Regardless, it presents good research and some interesting theories and arguments, even if I don’t entirely agree with all of them (but some are excellent!). I very highly recommend this one!
    • A previous review I wrote on it, for academic purposes: An excellent book on werewolves, even if some of the information seems irrelevant to the study of lycanthropy itself, particularly the earliest chapters on prehistory. Regardless, all of it is good information, and Beresford is very skilled at presenting his findings and argument. Very highly recommended. Also be sure to look up his publications on other folklore, such as vampires.

That should get you started on werewolves! I could recommend more, certainly, but those are my favorites. Also AVOID a publication called The Werewolf Book by Brad Steiger. It’s loaded with ridiculous false information. The same applies to his vampire book.

As for vampire books, I have an even wider library on those since they are honestly more common, but I’ll try to list only a few of my favorites:

  • From Demons to Dracula: The Creation of the Modern Vampire Myth, by Matthew Beresford – This is almost certainly my favorite book on vampires in folklore. It’s well written and well presented, just like Beresford’s book on werewolves, and I admire his work. He’s done excellent research and presents it in an orderly fashion, covering many vampire myths by type and explaining just how difficult it is to really study what we consider today as “vampires.” I consider it a must-have.
  • The Vampire in Lore and Legend, and Vampires and Vampirism, by Montague Summers – These books are not terribly accessible in terms of readability – that is to say, they might be likely to bore you to tears. But if you can push through it, they both contain a lot of very useful and interesting information, and they are essentially necessary for properly studying these legends.
  • The Secret History of Vampires: Their Multiple Forms and Hidden Purposes, by Claude Lecouteux – This is an odd little book and one I enjoyed reading. Well researched information and well presented. I recommend it.
  • Transylvanian Superstitions by Emily Gerard and Agnes Murgoci – While not exclusively about vampires, this is a very short and very interesting book loaded with lots of captivating information.

Hope this helps!