In this lecture Ben Fine aims at stimulating interest for and explaining the relevance of Marxist Political Economy. Ben Fine dedicates the first half of his comprehensible lecture to the question on how mainstream economics became the way it is by explaining its key concepts and how those evolved during the past 150 years. While critically reflecting those concept he also emphasizes that mainstream economics does not consider historical processes. This is the point of departure on his presentation of the core terms and crucial categories of Marxist Political Economy: e.g. the production process and class relations (Part 1). Part 2 examines the consequences of the capitalist mode of production and its propensity to crises. Ben Fine illustrates this Marxist analysis with the example of the current crisis and explains current conditions for the accumulation of capital.