Mobility and Ancient Society in Asia and the Americas is a collection of chapters addressing the long-standing questions of when and how modern humans colonized the Americas. The book, originally presented as proceedings of the Second International Conference on “Great Migrations,” is comprised of 13 chapters tracing the migration from Asia to the Americas. Many of these chapters summarize current research related to key lines of evidence, including molecular genetics, human cranial morphology, linguistics, paleogeographic reconstructions, and archaeology, and others present new perspectives on how ancient mobility impacted the peopling of the Americas.

Our understanding of the peopling of the Americas has greatly benefited from an interdisciplinary approach, and one line of evidence that has been integral in building testable migration models is molecular genetics. The chapter by Schurr summarizes the contributions of molecular genetics in explaining first American origins and the peopling process. The author traces genetic links between the Altai-Sayan region and modern Native American populations. He concludes that Southern Altaians and Native Americans shared common ancestry 25,000 years ago. After expansion into Beringia, MtDNA and Y-chromosome haplogroups diversified during an incubation period. In a single major migration, the Amerind population spread out of Beringia and throughout the Americas 15,000–20,000 years ago. This was followed by later Holocene-age circumarctic expansions. Genetic studies indicate these ancient populations gave rise to modern Native Americans.

Hubbe, Neves, and Harvati review cranial morphological analyses of a Late Pleistocene/Early Holocene sample of early Americans from Mexico and South America and present an alternative model of the peopling process. The authors argue that the morphological differences between the early American (predating 7,000 years ago) and recent Native American crania are too large to accommodate a single migration and subsequent in-place evolutionary change; instead, and unlike most geneticists, they support a dual dispersion model, with the earliest Americans retaining ancestral Upper Paleolithic traits. Further, the authors propose the retention of Old World ancestral traits suggests the migration from East Asia into the Americas was a rapid process with no evidence of an incubation period because early Americans did not evolve cranial traits adapted for the cold environment of Beringia.

Nichols reviews linguistic evidence to estimate the timing of the peopling of the Americas. The author argues that the great number of distinct language families in the Americas and time required for this extent of diversification point to a much earlier colonization than genetic, paleogeographic, and archaeological evidence suggest. Further, based on the linguistic population structure, colonizing populations were primarily coastal, moving in a counterclockwise direction along the Pacific Rim to southern South America, and later populations migrated along an inland route via Beringia.

The chapters by Dixon, Erlandson and Braje, and Anderson and Bissett link paleogeographic reconstructions, built with glacial mapping, radiocarbon dating, and sea level rise, to archaeological evidence to understand how changes on the paleolandscape impacted routes of colonization. All of these authors point to the biologically viable corridor along the Northwest coast as the most likely route for entry. While Dixon models glacial sequences for the opening of the coastal corridor, Erlandson and Braje build the archaeological evidence for this route, and Anderson and Bissett model how early Americans moving along the coast eventually accessed the North American interior.

Other chapters of this book offer new perspectives for understanding the peopling process. For example, Frachetti models mobility through an archaeological analogy between Bronze Age pastoral societies of southeastern Kazakhstan and ancient Asian and Trans-Beringian hunter-gatherers, ultimately addressing the question of what inspired ancient populations to push into unknown regions. Ives's chapter applies traditional anthropological principles to address the colonization of the Americas and build a model of the social landscape. The author invokes theory related to hunter-gatherer kin structures to argue that the colonizing populations focused efforts on “local group growth,” maximizing access to spouses to ensure multigenerational success in dynamic late Pleistocene environments (p. 149).

Mobility and Ancient Society reminds us that there is still work to do. There are many questions about the great migration from Asia to the Americas that remain unanswered. How do we reconcile discrepancies between models built from various lines of evidence? We gather new data and develop new methods to continue to test them. It is important to note that many of these chapters are concise summaries of previous research. Readers looking for an in-depth understanding of the evidence and analysis will need to consult articles published and referenced by the authors. This is not a shortcoming; instead, Frachetti and Spengler have made the work of these researchers accessible and prime for testing.