1 Introduction In this Virtual Special Issue of the American Journal of Human Biology, Guest Editor Ben Campbell and colleagues examine some of the major advancements in the study of the human biology of pastoralists over the last 20 years. This Special Issue is based on a Symposium from 2024 at the 49th Annual Meeting of the Human Biology Association, “Tribute to Michael Little: Last 20 Years of Human Biology Research among Pastoralists”.