200 years ago the founder of scientific socialism and arguably the greatest thinker of modern times, Karl Marx, was born. To celebrate, on Saturday 5 May in London, Socialist Appeal (the International Marxist Tendency in Britain) held Marx in a Day: a series of talks and discussions exploring Marx’s revolutionary ideas and political activity. The event was a great success, with around 80 workers, activists, students, and young people from across the country and even as far away as Paris coming along and taking part.