Introduction - the myth and the magic. From antiquity to the Middle Ages; indigo's heyday, the downfall of Woad and the salvation by denim; indigo plants and the making of their dye; blue nails - indigo dyeing worldwide; the variety of decorative techniques; for richer, for poorer - textiles prestigious and popular; blue art; "in sickness and in health" - blue beards, blue bodies; into the future. Appendix: chemical formulae.