James Clerk Maxwell (1831-1879) is arguably the father of electromagnetism, and unarguably one of the greatest physicists ever. Einstein called Maxwell's equations 'the most important event in physics since Newton's time, not only because of their wealth of content, but also because they form a pattern for a new type of law'. This unit will examine Maxwell's greatest triumph, the prediction that electromagnetic waves can propagate vast distances through empty space and the realisation that light is itself an electromagnetic wave. 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.