My reluctance to recommend the book stems also from Wade's discussions of 'race' and biology. I agree with Wade that there is something biological about racial categories. In my opinion, although racial identity is socially negotiated, people use physical traits as cues when 'assigning' a racial identity to themselves or another individual. Racial categorization isn't blind to biology. ... Although one might detect biological differences between races, any highlighting of the racial categories (just a subset of groups with biological correlates) has social costs, according to recent social science research. On the other hand, Neil Risch, cited often in the book, has argued that there are significant (medical) costs of ignoring the relationship between racial categories and biology. I suggest that these different costs be weighed in each circumstance where one might link 'race' and genetics. Wade's broad description of races as clearly delineated biological entities is unjustified in the context of a book about human history intended for a general audience. Why use the term 'race', when 'geographic ancestry' or 'continental origin' are more accurate and less costly in social terms, especially since Wade's definition of 'race' is "continent of origin"? I suggest acknowledging the correlation between racial labels and continents of origin, and saving the term 'race' for contexts in which social costs are outweighed by other costs.

Given the rich content of Nicholas Wade's latest book, Before the Dawn, I wish I could simply recommend the book, describe its highlights and stop there. Wade provides a valuable overview of the last ten years of scientific literature on genetic insights into the history of our species. He is an excellent storyteller, weaving the scientific results into a thrilling tale of human migration and settlement, competition and warfare, cultural and linguistic evolution and environmental challenges. The history of our species is a fascinating one, and Wade brings it to life.

I congratulate Wade for taking great pains to qualify many of his statements with terms such as "seems" and "appears to." In an important, related vein, early in the book he notes that any "intent" suggested in biologists' statements about evolution reflects shorthand communication and is not meant to imply that evolution has any particular goal "in mind." Evolutionary biologists will certainly appreciate that note. Furthermore, given that few readers will be specialists in all the fields represented in the book (paleoanthropology, archaeology, linguistics, genetics and more), many will appreciate Wade's practice of defining terms.

Despite the book's many strengths, I am reluctant to recommend the book unconditionally. I found some sections of the book challenging to read, as I looked for supporting evidence for various claims. For example, Wade suggests that the San, peoples in southern Africa who subsist via foraging, are the "closest living approximation to the ancestral human population." Behaviorally, this might be true. However, Wade goes on to suggest that the San may not have evolved genetically, as "foragers have presumably had much the same environment for the last 50,000 years." Wade appears to be unaware of the diverse environments even today within sub-Saharan Africa; furthermore, the changing global climate over the past 50,000 years has often had dramatic impacts on humans living in Africa.

Although at many points in the book Wade notes the speculative nature of conclusions from genetic, archaeological or geographic data, he occasionally treats those conclusions as fact elsewhere. For example, he writes, "There is no way to know for certain the nature of the interaction between the two human species [anatomically modern humans and Neanderthals]." Yet elsewhere he writes, "...[the Neanderthals] crushed the attempt by anatomically modern humans to penetrate the Levant." The reader is at risk of being lulled by numerous "maybes," "seems" and "appears" into trusting unsupported but confidently stated comments elsewhere in the book.

My reluctance to recommend the book stems also from Wade's discussions of 'race' and biology. I agree with Wade that there is something biological about racial categories. In my opinion, although racial identity is socially negotiated, people use physical traits as cues when 'assigning' a racial identity to themselves or another individual. Racial categorization isn't blind to biology. Yet Wade puts words in the mouths of the American Anthropological Association (AAA) when he states that the AAA "dismisses the idea that biological differences can be recognized between races." He backs up his statement with an AAA quote that makes a different point: "any attempt to establish lines of division among biological populations [is] both arbitrary and subjective." Although one might detect biological differences between races, any highlighting of the racial categories (just a subset of groups with biological correlates) has social costs, according to recent social science research. On the other hand, Neil Risch, cited often in the book, has argued that there are significant (medical) costs of ignoring the relationship between racial categories and biology. I suggest that these different costs be weighed in each circumstance where one might link 'race' and genetics. Wade's broad description of races as clearly delineated biological entities is unjustified in the context of a book about human history intended for a general audience. Why use the term 'race', when 'geographic ancestry' or 'continental origin' are more accurate and less costly in social terms, especially since Wade's definition of 'race' is "continent of origin"? I suggest acknowledging the correlation between racial labels and continents of origin, and saving the term 'race' for contexts in which social costs are outweighed by other costs.

Wade's chapter on language is replete with details of relationships among languages, methodology for reconstructing those relationships and arguments in support of methods that are purported to give ages of languages. Although much of this discussion will undoubtedly provoke many linguists, the most provocative element in this chapter is a more general statement: "The mutability of language reflects the dark truth that humans evolved in a savage and dangerous world in which the deadliest threat came from other human groups." I see little support for this conjecture. Language, at least a language rich in elements, cannot come into being without being mutable. And as Wade notes earlier in the book, "Language would have made small groups more cohesive, enabled long-range planning and fostered the transmission of local knowledge and learned skills." Mutability may reflect these advantages rather than a "savage and dangerous world."

Where I am familiar with the relevant scientific literature, I see the details that Wade includes in this, his latest book, as accurately representing scientific findings. Wade often wraps these scientific details in dramatic stories, thereby creating a book both informative and entertaining. However, some of Wade's general themes, such as his claim of a very high level of aggressiveness of prehistoric hunter-gatherers, are just that—dramatic stories. Readers will benefit most by considering each such claim as one among several plausible interpretations of the data.