I recently let people know I was selling some of our library's overflow at Half.com. We are planning our relocation, and nine bookshelves is a lot to move. Most of these books are fiction or were purchased for college classes, but there are some occult/Pagan books there as well. These cover topics I researched at different points in my path, but set aside with time.
So, which books am I keeping as important sources to my tradition? This might be the better question.
I follow a Hellenic path. I pursue this path seriously, even serving time for a while as a grad student in classical languages and literature. I also spent a lot of time reading Greek history, and many of the 'facts' invoked in popular neo-Pagan materials about the ancient Greek gods are wrong. If a book fulfills one of your spiritual purposes, by all means use it to better your life, but don't swallow all claims as factual. Many footnotes in these books cite other neo-Pagan sources instead of scholarly works, assuming that other Pagan authors have done the research for them.
Accuracy is especially important if you explain your religion to Xian fundamentalists. Many of the heavy-duty debaters have studied history, or will at least crack a book to prove you wrong. You will come off looking like an idiot, and will reinforce the image of Pagans as either liars or misled lambs. Know your stuff.
Primary Sources
Many of these authors can be found in your public library, or online at Perseus.
The Homeric Hymns (These are written in the Homeric style, but may not be by 'Homer', if such a poet existed. I like the Boer and Lattimore translations)
Homer: The Iliad and The Odyssey
Hesiod: Theogony, Works and Days
Important authors: Euripedes, Aeschulyus, Aristophanes, and Sophocles. Poets like Sappho are also useful for gleaning invocational lines. The philosophers make useful reading, but remember that their works introduce new ideas rather than explain old traditions. Two dialogues by Plato, Timaeus and Critias, mention the story of Atlantis, if you are including this in your tradition. Plato also has several other dialogues that explore the nature of the gods in some way or another. Metaphysics, by Aristotle, is a little hairy for beginners but is thought-provoking.
Historical and Cultural
The ancient Greek and Roman religions are among the best documented of the ancient religions. The majority of the sources below cover when, where, and how the ancient Greeks performed their rites. I'm not suggesting you should adopt all the practices you read about (animal sacrifice gets a bit messy), but these books may spark new ideas or explain aspects of the Greek gods that have puzzled you in the past.
Walter Burkert: Greek Religion, Ancient Mystery Cults, and Structure and History in Greek Mythology and Ritual, Homo Necans
H.W. Parke: Festivals of the Athenians
Martin P. Nilsson: The Mycenaean Origin of Greek Mythology
W.K.C. Guthrie: The Greeks and Their Gods, Orpheus and Greek Religion
Carl Kerenyi: Eleusis: Archetypal Image of Mother and Daughter, The Gods of the Greeks, Goddesses of Sun and Moon
Pagan-Oriented Writings
Drew Campbell: Old Stones, New Temples (Modern reconstructions of ancient Greek rites. I bought this book off XLibris, but you may have better luck finding a copy through Hellenion.)
David Godwin: Light In Extension (An excellent rundown of Greek magical practices through time.)
Murry Hope: Practical Greek Magic, The Elements of the Greek Tradition (I had to write England to find out how to get a copy of the latter; I hope it is back in print if you're interested in it. Ignore the sections on Atlantis and Sirius, unless that's included in your tradition. A little woo-woo for me. PGM focuses on personal/magical applications of Greek imagery, and describes the Heroic Path. Hope is the first to say these aren't historical, but that doesn't mean they're not useful or rewarding.)
Jean Houston: The Hero and the Goddess Believe it or not, this is a set of psychological exercises that take you through the Odyssey.
I hope this list of materials is helpful for people hoping to broaden their library or expand their spiritual practices. I would suggest that you start by reading the Homeric Hymns and then branch outwards. Introduce the scholarly materials slowly, preferably one at a time, or you'll be risking brain bogglage. Over time, you will begin to feel more firmly rooted in your tradition, and more competent to share with others.
Thank you for your time, and Blessed Be,
Sarah G