Spencer is so grandiose that it is hard to summarize his ideas, yet he was one of the most influential thinkers in nineteenth-century Britain, and his ideas were an inspiration around the world. His version of evolution was utterly generalised in all the ways Darwin tried to be circumspect. The organic analogies which Spencer developed are the foundation-stones for the widespread idea of functionalism across the biomedical and human sciences, extending to architecture, systems theory, cybernetics and information theory. I have written in detail about his ideas in many books and essays. An invitation from the editor of History Today led to this attempt briefly to circumscribe Spencer's work and impact. The essay was reprinted in a collection from the journal: G. Marsden, ed., Victorian Values. Longman, 1990.