The document discusses interaction design patterns for mobile devices. It identifies key challenges for mobile interaction as small screens, difficult text input, and slow connections. It then provides examples of patterns that address dividing content, navigation, and information presentation for small screens. For difficult text input, it discusses patterns like autocompletion, dropdown choosers, and illustrated choices. It also describes gestural interaction patterns from sources like tapping, pinching, and dragging. The document aims to provide solutions to usability problems in mobile interaction design.