Whenever you get dressed, carry objects, write, draw, or gesture, you express knowledge about how to get things done with your hands. Ironically, that knowledge is often difficult to express. Typically you can't say what you know. Still, it would be enormously useful to identify the knowledge underlying manual control. The design of equipment and transportation systems might better anticipate the abilities and limitations of users, and methods of teaching and rehabilitating skills might improve. This book, the first on the cognitive psychology of manual control, uncovers the hidden knowledge that hands express. Organized around key topics in this emerging area, including the role of the will in manual control, illusions concerning hand position sense, and the coordination of manual actions with others, Knowing Hands explains the planning and control of manual actions in everyday life.