Exciting new advances in DNA sequencing and genotyping technology have begun to reveal the depth and significance of genomic variation among organisms. The causes of this variation are evolutionary, and the amazing accumulation of data on the genomic scale has firmly positioned population and evolutionary geneticists at the center of this biological revolution. Our research combines the power of genomic data with concepts and tools from population genetics to draw insights on deep, long-standing questions about the evolutionary process and the nature of genetic variation.