This is the first comparative study of ideas and politics in France, Germany, the US, and Great Britain between 1870 and 1920 - a period when two generations of European and American intellectuals created a transatlantic community of philosophical and political discourse. In particular, it demonstrates how a number of thinkers from different traditions converged to create the theoretical foundations for new programmes of social democracy and progressivism.'finely researched and imaginative survey ... an interesting and important contribution to the history of political philosophy.' Journal of American History