The philosopher WB Gallie argued many years ago that there could be no simple definition of words such as' freedom'because they embodied what he called'essentially contested concepts'. They were words whose meaning had to be fought over and whose compteting definitions arose out of political struggle and conflict. Imperialism, and its close ally, colonialism, are two such contested concepts. This set will give readers an insight in to the main lines of debate about the meanings of imperialism and colonialism over the last two centuries.