Dr. Clark has been working on methods for statistical inference of population genetic attributes of population samples since obtaining his PhD at Stanford in 1980. He has published more than 360 peer-reviewed papers in the field of population genetics, and is co-author with Dan Hartl of Principles of Population Genetics. His work is split between efforts in human and Drosophila empirical population genetics, with an emphasis on computationally challenging statistical methods, and on theoretical population genetics, including large simulation studies. He has contributed to the inference of haplotype phase from population genetic samples, to inference of natural selection from genome-wide data, and to inference of past demography from sample genotype data. Many projects have a common theme of relating variation and genotypic and phenotypic levels, which integrates understanding of gene regulatory networks and modern genome-wide approaches to quantitative genetics.