Patrick: "Evolutionary game theory is an approach that was originally developed in biology, but there are now many applications. And, it seems to me to be an approach that is quite conformable with Marx's methodology. My hope was that I'd be able to find a reference that directly connects Marx's methodology to Darwin's methodology." Your approach seems quite pragmatic! You can check, for example, the following letters: 1. Marx to Lasalle, Jan 16, 1861. 2. Marx to Engels, June 18, 1862. 3. Engels to Albert Lange, March 29, 1865. 4. Marx to Engels, March 25, 1868. 5. Marx to Kugelman, June 27, 1870. 6. Engels to Lavrov, Nov 12, 1875. There are also one or two footnotes in Capital I. I don't think you will find a *direct link* between Marx and Darwin methodologies. Marx seems to stress the importance of the "evolutive" view as it is not an *ahistorical methodology*. But, regarding, what one can call the "Malthusian" source ("struggle for existence") of Darwin theory, it seems to me that Marx, and even Engels, are rather quite ironic. And, maybe, this would be the link you are looking for. Alejandro R.