A method of interacting with printed content using a handheld display device. The method includes the steps of: imaging an area of a printed substrate and generating image data using an image sensor; determining interaction data using the image data, retrieving display data using an identified page description, the display data corresponding to the printed content; displaying, on an opaque touch-sensitive display screen of the handheld display device, display information based on the display data; and interacting with the display information via the opaque touch-sensitive display screen. The opaque touch-sensitive display screen has real-time virtual transparency through the screen to the printed content from a user's perspective to provide a virtual window to the printed content.