Brenneman, Walter L., Jr. & Mary G., 1995. Crossing the Circle at the Holy Wells of Ireland. Charlottesville, VA, USA & London: The University Press of Virginia. ISBN 0-8139-1548-1.
Bridges, Marilyn, no date. Markings: Aerial Views of Sacred Landscapes. Oxford, UK: Phaidon Press Ltd. Outstanding pictures from the air of sacred sites around the world.
Cope, Julian, 1998, The Modern Antiquarian: A Pre-Millennial Odyssey Through Megalithic Britain. London: Thorsons. ISBN 0 7225 3599 6. A wonderful whimsical guide to Britain's ancient sacred sites. A nice touch - the author gives his personal subjective impressions of many sites. Includes a Gazetteer to over three-hundred Prehistoric Sites. You might want to take this one with you.
Devereux, Paul, 1992. Secrets of Ancient and Sacred Places. London: Blandford Press. Sacred spaces around the world.
Hancock, Graham, 1995. Fingerprints Of the Gods: A Quest For the Beginning and the End. London: Heinemann. A different putting together of evidence from prehistory that does not lead to ETs, but rather to a technologically advanced civilization on this planet in 10,000 BCE.
Harbison, Peter, 1970. Guide to the National Monuments in the Republic of Ireland. Dublin: Gill & MacMillan. Still good after all these years - if you can find it.
Historic Monuments of Northern Ireland. 1987. Department of the Environment For Northern Ireland, Belfast: Her Majesty's Stationery Office. Good overall view of sacred sites in Northern Ireland.
Lippard, Lucy R., 1983. Overlay: Contemporary Art and the Art of Prehistory. New York: Pantheon Books. Using the Earth as a canvas for art. Sacred spaces as Earth Art.
Mann, Nicholas R. 1996. The Isle of Avalon: Sacred Mysteries of Arthur and Glastonbury Tor. St Paul, MN, USA: Llewellyn Publications. ISBN 1-56718-459-6. A wonderful overview of Glastonbury combining the ancient Christian and Arthurian material with more recent discoveries like the Maltwood figures (the Glastonbury Zodiac), the Michael Line, the Tor labyrinth and the sacred geometry of Glastonbury Abbey.
McMann, Jean, 1993. Loughcrew: The Cairns - A Guide. Oldcastle, Co Meath, Ireland: After Hours Books. A good guide to an important Neolithic passage-graves site West of the Boyne Valley.
Michell, John, 1988. The Traveller's Guide to Sacred England. New York: Alfred A Knopf. A guide to the legends, lore, and landscape of England's sacred places. Written by one of the best.
Pepper, Elizabeth & John Wilcock, 1993. Magical and Mystical Sites: Europe and the British Isles. Grand Rapids, Michigan: Phanes Press. A good one if you're traveling around Europe.
Streep, Peg, 1994. Sanctuaries of the Goddess: The Sacred Landscapes and Objects. Boston: Little, Brown and Co. Sites in Europe and the Mediterranean.
Westwood, Jennifer, editor. The Atlas of Mysterious Places. New York: Weidenfeld & Nicholson. Another tour of sacred places in the Americas and Europe.