This is a truly excellent work, readable and informative at A to A+ quality, and the subtitle is Ancient DNA and the new Science of the Human Past. It has occasioned some public controversy for its discussion of race and genetics, but most of all this is a book about how science is done. For instance, the page and a half discussion of how researchers try to ensure that human DNA does not contaminate Neanderthal DNA is just beautiful.
Here is one good summary passage:
The case of the Ancient North Eurasians showed that while a tree is a good analogy for the relationships among species — because species rarely interbreed and so like real tree limbs are not expected to grow back together after they branch — it is a dangerous analogy for human populations. The genome revolution has taught us that great mixtures of highly divergent populations have occurred repeatedly. Instead of a tree, a better metaphor may be a trellis, branching and remixing far back into the past.
Here is another excerpt of note:
Analyzing our data, he [Iosif Lazaridis] found that about ten thousand years ago there were at least four major populations in West Eurasia — the farmers of the Fertile Crescent, the farmers of Iran, the hunter-gatherers of central and western Europe, and the hunter-gatherers of eastern Europe. All these populations differed from one another as much as Europeans differ from East Asians today.
The concept of “ghost populations” will enter your mental conceptual vocabulary. And:
The extraordinary fact that emerges from ancient DNA is that just five thousand years ago, the people who are now the primary ancestors of all extant northern Europeans had not yet arrived.
Most of all, this is a science book, not a “race book.” (“Having been immersed in the ancient DNA revolution for the past 10 years, I am confident that anyone who pays attention to what it is finding cannot come away feeling affirmed in racist beliefs.”) You may know that Reich is a Professor of Genetics at Harvard Medical School.
Here is his earlier NYT essay (though I think the very first link in this post is the best place to start, do read that carefully), well done but not quite representative of the book either. You can buy it here, this is definitely one of the books of the year and one of the best popular science books of any year.