How does the computer's peculiar binary world of digital entities differ from our analogue world of colour, sound, taste and touch? This unit explores the way in which information, in the form of text, still and moving images, and sound can cross the boundary from the analogue universe into a digital world. This study unit is just one of many that can be found on LearningSpace, part of OpenLearn, a collection of open educational resources from The Open University. Published in ePub 2.0.1 format, some feature such as audio, video and linked PDF are not supported by all ePub readers.