I found a link to a wonderful online historical needlework book on the Project Gutenburg website. It downloads quickly (on my computer at least) and the pictures are beautiful and very clear. I'm absolutely fascinated by the alphabet done in some kind of embroidered braids. And I love the practical directions for transferring the design onto the fabric.
Encyclopedia of Needlework by Therese de Dillmont
This is the table of contents. The links don't always seem to work, but sometimes you can click on the titles for a direct link to the pages :-)