An International Correspondence Schools textile technology text on dobbies and other head motions, the mechanisms that raise and lower loom harnesses for weaves too complex for cam looms. It explains dobby parts (knives, jacks, hooks, fingers, chain cylinders), how chain drafts are turned into wooden, paper or punched pattern chains, and how dobbies are connected to harnesses by sheaves, straps and connectors. Later sections cover cleaning and maintenance, timing, variations such as punched-chain, Staubli and multiplier dobbies, the butterfly motion, and a heavy-duty head motion with its drive gearing. It is illustrated with many line drawings and ends with review questions.