If you are a dyer or want to experiment with creating your own skeins of colored yarns, Gene Shepherd's comprehensive guide of dyeing techniques for fiber artists "prepared to DYE", will show you the way. If you have never dyed before, "courage" is what Gene says you will need to "push the edges...to surpass your wildest dreams" in this process book.
Gene is a rug hooker, so the book includes dyeing wool as yarn as well as cloth. Multiple photographs on every page will add to your 'getting started', 'dyeing in batches' with commercial acid dyes and 'dyeing without dye'. There are nineteen step by step demonstrations of dyeing methods from dump, spot, marbleizing, bleeding...for wool and techniques for mohair, nylon and more.
'Traditional multivalue swatches' can create a half dozen or more colors in the same value. 'Lazy swatches' does something similar but without all the measuring. The 'bleeding wool' section was fascinating and new to me. You can "recycle dye" from a piece of deeply color saturated wool cloth or even a dyed skein of yarn. Use this, to dye a new skein of yarn.
Whether or not you try all the various ways of dyeing fiber...just reading what Gene has to say, will expand your knowledge and creative use of color. If you know a rug hooker...tell them about this book.
Meet Gene in this dye video: http://www.youtube.com/watch?v=-Sz3jNeMU1Y . He is dyeing wool cloth. Wool yarn should be turned down to a simmer. When the bath has cooled a bit, add yarn. You don't want the yarn to felt.