Recommended Books:
What Witches Do - Stewart Farrar
A Complete Guide: Witchcraft - Theresa Moorey
A Witch Alone: Thirteen Moons to Master Natural Magic - Marian Green
Natural Witchcraft - Marian Green
Circle of Fire: The Symbolism and Practices of Wiccan Ritual - Sorita D'Este & David Rankine
A Witches Bible - Janet & Stewart Farrar
Also available as two separate volumes titled:
Eight Sabbats for Witches - Janet & Stewart Farrar
The Witches' Way - Janet & Stewart Farrar
Wicca: The Old Religion in the New Millennium - Vivienne Crowley
Natural Magic - Doreen Valiente
ABC of Witchcraft Past & Present - Doreen Valiente
Recommended Fiction
High Magic's Aid - Gerald B. Gardner
The Sea Priestess - Dion Fortune
Moon Magic - Dion Fortune
Mists of Avalon series - Marion Zimmer-Bradley
What is Wicca? - by Vivienne and Chris Crowley
The History of Wicca: 1939 to present (PDF) - by Julia Phillips (used with permission)
Gerald Gardner: History and Articles - from The Wica website
The Old Ways in New Times - by Cian MacFhiarais
Venus Figurines in Prehistoric Europe - by Cian MacFhiarais
Summer Solstice at Avalon - by Paul Mountfort
Beth & Berkana: Birth and Birch in Celtic and Norse Traditions - by Paul Mountfort
The Goddess Arrives: The Novels of Dion Fortune and the development of Gardnerian Wicca
Simon Goodman: Magister - A memorium
Witchcraft Today - by Gerald Gardner (non fiction)
The Meaning of Witchcraft - by Gerald Gardner (second non-fictional work)
High Magic's Aid - by Gerald Gardner (a fictional work)
Gerald Gardner: Witch - Gardner biography attributed to Jack Braelin but written by Idries Shah
Witchcraft in Western Europe - by Dr. Margaret Murray
God of the Witches - by Dr. Margaret Murray
Aradia: Gospel of the Witches - by Charles Leland (1890)
The Golden Bough - by Sir James George Frazer
The Magus - Francis Barrett
Trials of the Moon: Reopening the case for Historical Witchcraft - by Ben Whitmore (we would also suggest purchasing this excellent book and supporting the author who has generously made most of it available free online.) Order it here!
Lady of the Earth - a collection of articles & resources on many topics
A Modern Herbal - online version of the book of the same name
Culpeper's Complete Herbal - medicinal and occult properties of plants
Earth Witchery - a great resource for ideas for celebrating the Sabbats, including food, ritual crafts, correspondences etc
The Witches Sabbats - a website by Mike Nichols
The Hermetic Library - a large collection of occult and esoteric writings, articles, and books.
Sacred Texts - an online library of books (with expired copyright) and articles on a range of spiritual topics. Sections on Neopaganism/Wicca, Occult/Esoteric, Celtic Mythology, and Astrology are particullary worth a look.