Eleven years ago, Annette Gordon-Reed, then known primarily as a lawyer, left her zone of professional comfort to publish a book about slavery. Those who know the early history of the United States will recognize the enormity of her entry into a race-charged debate simply by reading the title of that 1997 book: "Thomas Jefferson and Sally Hemings: An American Controversy."

Yes, that Thomas Jefferson, the former president of the United States, the sage of Monticello, perhaps the most admired of the Founding Fathers. Yes, that Sally Hemings, the slave who allegedly had become Jefferson's mistress and mother of his children.

Gordon-Reed did not write that book to promote sensationalism nor to become wealthy. Her documentation reached impressive heights. Her choice of publisher, the University Press of Virginia, meant scholarly integrity and much lower sales than if she had chosen, say, Random House.

Herself of African-American heritage, Gordon-Reed wanted to advance responsible discussion about race, set straight the American historical narrative, and assure that Hemings received her rightful place in history.

Now, Gordon-Reed returns to spread the word not just about Hemings, but about her lineage. "The Hemingses of Monticello" is a genealogical inquiry encompassing such a high degree of difficulty for an author that the result can only be described as awesome. Gordon-Reed has located mountains of information about generations of a slave family whose members left little direct documentation. She has also mined the life of Jefferson in an original way, woven informed speculation into the narrative, and produced a book of 800 pages that unfolds in a compelling manner. Such multigenerational sagas are usually reserved for famous whites (the John Adams family or the George Bush family). Gordon-Reed has altered the equation.

The details of the Hemingses' lives are fascinating (and often depressing). For many readers, however, the greatest value of the book will derive from the themes that Gordon-Reed establishes. What is the dynamic of a human being enslaving other human beings? How does that dynamic change across race lines, especially when children are born from this situation? In what ways does the dynamic look from the vantage point of the enslaved, as opposed to the view of the slave master?

As Gordon-Reed explains, "Sally Hemings is often treated as a figure of no historical significance -- a mere object of malicious personal gossip. That shouldn't surprise. Aside from forays into 'history from the bottom up' -- a perspective that has been given increased emphasis over the past forty years -- historical writing tends to favor the lives of individuals who spoke, acted, and had a direct hand in shaping whatever particular 'moment' they lived in. Hemings does not fit the bill on any of these accounts. She neither spoke publicly about her life nor engaged in any public acts that have been recorded. Others -- journalists, Jefferson's enemies -- determined how she entered the spotlight, and they put her there with no real interest in her as a person."

Because of Gordon-Reed, Hemings and her ancestors and descendants achieve full personhood. For that, the author deserves praise and lots of readers. Not so incidentally, because of her achievements Gordon-Reed is now a law professor at New York University and a history professor at Rutgers University.

Author Steve Weinberg's most recent book is "Taking on the Trust: The Epic Battle of Ida Tarbell and John D. Rockefeller." He lives in Columbia, Mo.