Every knitter has her favorite supplies and tools. Here are some of mine.
Budd, Ann. Sock Knitting Master Class: Innovative Techniques + Patterns from Top Designers. Loveland, Colo.: Interweave, 2011.
Bush, Nancy. Folk Socks: The History & Techniques of Handknitted Footwear. Loveland, Colo.: Interweave, revised edition 2012.
Gibson-Roberts, Priscilla. Ethnic Socks & Stockings: A Compendium of Eastern Design & Technique. Sioux Falls, S. Dak.: XRX Books, 1995.
Neel, Lara. Sock Architecture: Heels, Toes, & Techniques for Knitting Awesome Socks. Lakewood, Ohio: Cooperative Press, 2014.