So yeah, Karl Marx's beard, it's my great regret to inform you that there are some paltry beards trying to take up the class struggle these days. Best wishes, John Green. Although he's often considered the father of communism because he co-wrote the Communist Manifesto, Marx was above all a philosopher and a historian. It's just that unlike most philosophers and historians, he advocated for revolution. His greatest work, Das Kapital, sets out to explain the world of the 19th century in historical and philosophical terms. Marx's thinking is deep and dense and we're low on time, but I want to introduce one of his ideas, that of class struggle. So for Marx, the focus isn't on the class, it's on the struggle.