There are many books today dedicated to the Great Goddess not to mention Goddess sacred lore and women's spirituality in general. The following are only a few recommended books, including a number of "classics" which are available.
"Ancient Mirrors of Womanhood" by Merlin Stone
"When God was a Woman" by Merlin Stone
"Mysteries of the Dark Moon" by Demeter George
"The Once and Future Goddess" by E Gadon
"The Myth of the Goddess: Evolution of an Image" by A Baring and J Cashford
"The Living Goddess" by M Gimbutas
"Celtic Goddesses: Warriors, Virgins, Mothers" by Miranda Greene
"Priestess of Avalon, Priestess of the Goddess" by Kathy Jones
"Pagaian Cosmology" by Glenys Livingston
"Queen of the Night. Rediscovering the Celtic Moon Goddess" by S. MacLeod Nic Mhacha
"The Goddess and the Warrior" by N Marinatos
"The Goddess Path" by Patricia Monaghan
"Ariadne's Thread" by S Mountainwater
"Shakti Woman" by Vicki Noble
"The Great Cosmic Mother" by Monica Sjöö and Barbara Mor
"The Earth Goddess: Celtic and Pagan Legacy of the Landscape" by C Straffon
"Women’s Encyclopaedia of Myths and Secrets:" by Barbara Walker
"Inanna. Queen of Heaven and Earth" by D Wolkstein and S Kramer