Chain Making Link by Link by Jeanne Jerousek-McAninch
This 127 page manual is a compilation of class handouts from a decade of the author’s classes. There are some purely chainmail patterns included, but most of the projects involve other fabrication and soldering, so you’ll need access to a torch. This is a fantastic resource for anyone serious about chain making. If you’re comfortable with a self-published format, then you should definitely buy a copy.