I am a population geneticist interested in how evolution works at the population, subspecies and species levels. My subjects of study are often butterflies. I combine a breadth of approaches that include field ecology, laboratory experiments, molecular population genetics, statistical theory, computer simulation and mathematical modeling. The field and laboratory experiments tell us about the ecological processes that create selection and adaptation to local conditions, and about the movements of different genotypes from place to place. The laboratory genetics tells us about the ability of genes to spread among populations, and about the genetic contribution to the phenotype. The statistical theory allows us to test hypotheses, and put both numerical values and estimates of error onto the processes we are interested in. The mathematical modeling and computer simulation allow us to figure out what processes are likely to be most important to measure in the first place, and computer simulation allows us to test the logic of these ideas when the explanations get particularly complex.