Recommended Reading (compiled from suggestions -- send yours in!):

Adrosko, Rita J.: Natural Dyes and Home Dyeing.  Dover Publications, 1971.  ISBN 0-486-22688-3.

Bliss, Anne: North American Dye Plants.  Interweave Press, 1993.  ISBN 0-934026-89-0.

Bolton, Eileen M.: Lichens for Vegetable Dyeing. ISBN 1-56659-001-9.

Buchanan, Rita: A Dyer's Garden. Interweave Press, 1995.  ISBN 1-883010-07-1.

Buchanan, Rita: A Weaver's Garden.   Interweave Press, 1987.  ISBN 0-934026-28-9.

Brooklyn Botanical Garden, Dye Plants and Dyeing. 1964.

Cameron: Woad.

Casselman, Karen Diadick: Lichen Dyes A Source Book, 1996, ISBN 0-9681021-0-7 (Studio Vista Publications, 2018 New Cheverie Road, Cheverie, Nova Scotia, Canada B0N 1G0)

Ciba Review: 1- Medieval Dyeing; 10 - Trade Routes and Dye Markets in the Middle Ages; 57 - Medieval Dress.

Duke, Dee and Rowena Edlin-White: The Medieval Dyepot

Dean, Jenny: Wild Color. Watson-Guptill Publications, 1999. ISBN: 0823057275.

Forbes, R.: Studies in Ancient Technology: Vol. III, Paints and Pigments and Vol. IV, Fibres and Fabrics.

Fraser, Jean: Traditional Scottish Dyes and How to Make Them.  ISBN 0-86241-575-6.

Goodwin, Jill: A Dyer's Manual. Pelham Books, ISBN 07207-1327-7.

Grierson, Su: The Colour Cauldron. Perth, Scotland: Mill Books, 1989. Book about the dyes used in the Scottish Highlands.

Kierstead, S. P.: Natural Dyes. Pub. 1920.

Kornerup, A. and H. Wanscher: Methuen Handbook of Colour. ISBN 0-413-33400-7.

Kowalchik, Claire and William H. Hylton, eds.: Rodale's Illustrated Encyclopedia of Herbs.  Rodale Press, 1998.  ISBN 0-87857-699-1  (hardback)  0-87596-964-X (paperback)

Liles, J.N.. The Art and Craft of Natural Dyeing: Traditional Recipes for Modern Use Knoxville, Tennessee: The University of Tennessee Press, 1990.

McRae, Bobbie A.: Nature's Dyepot: A Resource Guide for Spinners, Weavers, and Dyers. Austin, Texas: Fiberworks Publications, 1991. ISBN 0-944577-02-4

Ponting, K. G.: A Dictionary of Dyes and Dyeing. ISBN 0-7135-1311-X.

Rice: Mushrooms for Color.

Robertson, Stuart: A History of Dyed Textiles.

Sandberg: Indigo Textiles.

Sandberg: The Red Dyes: Cochineal, Madder, and Murex Purple, Lark books, 1994.  ISBN 1-887374-17-5.

Singer, C.: A History of Technology. (5 vols.)

Simmons: A Shetland Dye Book.

Smith, R. S.: A Woad Growing Project at Wollaton in the 1580's. Transaction of the Thoraton Society of Notts, 1961, Vol. LXV.

Todd, Carol: Earth Tones, Colors from Western Dye Plants, Todd Designs, 1995 ISBN 0-9667803-0-2.

Van Stralen: Indigo, Madder and Marigold

Weigle, Palmy: Ancient Dyes for Modern Weavers.  Watson-Guptill Publications, 1974.  ISBN 0-8230-0223-3. 

A Few Online Booksellers:

Interweave Press

Lark Books