Trained as a physicist at Harvard University, Cambridge, Massachusetts, USA, and Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA, he looks at evolution through the lens of simple mathematical models that capture only the most essential aspects of the problem. A major theme in his research is the interconnection of ecological and evolutionary processes. For example, he found that population expansions can both inhibit interspecific mutualism and promote intraspecific cooperation. Most recently, he became interested in population genetics models of cancer and the effects of deleterious passenger mutations on cancer progression. Kirill S. Korolev's homepage.