I hesitate to say any of this is essential for everyone, because it really depends on your path, and what you're interested in, but the books I've enjoyed and got the most out of include:
- John Michael Greer, 'A World Full of Gods' (general polytheism)
- Christine Hoff Kramer, 'Seeking the Mysteries: An Introduction to Pagan Theologies'
- Erik Hornung, 'The One and the Many: Conceptions of God In Ancient Egypt' (kemetic polytheism; don't let anyone tell you it's about monolatry, because it's not)
- Kenaz Filan and Raven Kaldera, 'Talking to the Spirits: Personal Gnosis in Pagan Religion'
- Richard Wilkinson, 'The Complete Gods and Goddesses of Egypt'
- Raven Kaldera, 'Hermaphrodeities' (queer paganism/polytheism)(though I'd have liked more non-binary stuff. /pedant)(then again, I've only read the first edition; IDK if the second edition is any better in this regard.)
- Nimue Brown, 'Druidry and the Ancestors'
- Alaric Albertsson, 'Travels Through Middle Earth' and 'Wyrdworking' (Anglo-Saxon polytheism)
- Faulkner's translation of the Book of the Dead (considered (one of) the best translation(s) out there)
- Paul Huson, 'Mastering Witchcraft' (the book that would have sold me witchcraft when I was first getting started if I'd read it first, instead of Silver Ravenwolf)
- Marco Zecchi, 'Sobek of Shedet: The Crocodile God in the Faiyum in the Dynastic Period' (...it's an academic book about Sobek.
- 'Hekate: Her Sacred Fires', edited by Sorita d'Este, was my introduction to Hekate in a more devotional form, and it both inspired me and scared the crap outta me. (In a good way.)
- Everyone should read the 'Principia Discordia' for lulz and good times.
I spent a long time, actually, not really reading Pagan books, and my library was quite dismal for many years until I started buying books again. So I feel like I'm still catching up. I still haven't got hold of any decent books on Greek and Roman polytheism, but that's partly due to it being lower on my list of things to research at the moment. I do have some saved on my Amazon wishlist, but I haven't got around to buying them yet. I only have so much money. I've also started acquiring some of the more classic Pagan/Wiccan books, for no other reason than I'm interested in reading those older books and to get a better idea of what Wicca was meant to be before the solitary eclectic neo-Wiccan stuff turned up and muddied the water.
There are certainly some I'd ask for my money back on, but I keep them, because I like knowing what I don't like, as much as I like knowing what I do like, and marginalia and arguments with authors is always great. Unless it's an ebook. I can't add marginalia to an ebook. Boo.
Well, okay, I won't keep shite Egyptian books, but I have kept the other ones listed down there, for 'arguing with the author' purposes.
Off the top of my head, books I haven't been so keen on are:
- any book on anything Egyptian that cites Budge as a source. Or doesn't cite any sources at all. (Okay, this is a general rule, rather than a specific book, but it still stands.)
- Rae Beth's 'Hedgewitch', which did not agree with me. Too much of the heteronormative Wiccish nonsense for my liking.
- Nimue Brown's 'Pagan Portals: Spirituality without Structure' also didn't agree with me. The tone of her writing put me off, and I felt her biases against any organised religious structure at all were coming through too strongly for me to feel like I could really engage with her arguments in a reasonable manner. Which is a shame, because I think this is a good topic that needs to be written about. Just. Not with the 'all groups are ebil!' mindset, plz.
- 'Lyblác: Anglo-Saxon Witchcraft' by Wulfeage - for pedantic 'I didn't like the organisation of the book' and 'will you explain some of these unexplained things plz' and 'can you fix these formatting errors they are terrible and you have misprinted a rune!' reasons. It is a solid book, with a good tradition outlined in it, and I don't even mind that it's Wiccish, because I did get inspired by some of the rituals and spells and charms in there, but nggrh, niggles. /pedant. I think it's been done better elsewhere, tbh.
- I've never been overly keen on Christian Jacq's writing, either. He does a lot of Egyptian themed books, and IDK. 'Magic and Mystery in Ancient Egypt' was good, but I'm lukewarm on the rest.