Interactive digital artworks are characterized by making the observers not only passive viewers, but also active co-authors of the work. Interacting with such artworks allows visitors to be part of a sophisticated process, to participate in changing and re/creating this process, or in exploring it using tools like joystick, mouse, or head-mounted display, or via specially created platforms. In some artworks, visitors can participate via non-material interfaces. Different research methods such as visual perception based on psychology, and established art historic comparative methods are put together to analyse these artworks. This book locates the interactive digital artworks in an art historic context, illustrating the character and development of pre-existing visual motifs from the palettes of Old Masters to contemporary interactive digital art.