Interactive Gestures: Designing Gestural Interfaces

I’m in the middle of writing chapter one of the book, which is an introduction to interactive gestures and gestural interfaces. Chapter one currently includes:

• Introduction
• Direct and Indirect Manipulation
• A Brief History of Gestural Interfaces
• The Mechanics of Touchscreens and Gestural Controllers
• The Attributes of Gestures
• The Ergonomics and Usability of Gestures
• and How to Determine the Appropriate Gesture

Is there anything else you’d like to see in an introductory chapter on this subject?