This article offers an introduction to Marxian economics for the uninitiated student or instructor. It first places Marxian economics within the surplus approach and ties Marx’s economic analysis with his theory of history, that is, historical materialism. The concepts of class, mode of production and antagonism are introduced. The article then discusses Marx’s analysis of capitalism. This is performed by first introducing the reader to the labour theory of value and then to the circuit of capital. The conflict between capital and labour and the conflict between capital and capital are explored around the question of technological change and innovation. This is followed by a brief discussion of the capitalist crises in the Marxian framework, after which the article concludes by presenting two strands of debate within Marxian economics.