helping to forge their racist ideologies. The authors do not support these and similar attempts to “hijack” Darwin for ends that would have horrified him. Rather, they want to understand what all groupshistorians, scientists, and ideologueshave failed to grasp“the moral fire that fueled hisobsession with human origins.” Even those already familiar with the antislavery views of Darwin’s forebears will be enlightened by the wealth of new information the authors have found that elucidates both the extent of British involvement in the slave trade and the efforts of committed abolitionists who devoted their time, money, and energies to eradicating this heinous practice. Abolitionists such as Thomas Clarkson and his many allies, including members of the Darwin family and the Wedgwoods (Darwin’s maternal relatives), succeeded in convincing the British government, in 1807, to outlaw its trade in slaves, though the practice of slavery was allowed to continue in the colonies.

By the time Charles Darwin was born in 1809, nearly two million Africans had been abducted and sold in British colonies. During his youth he absorbed the belief from his sisters and relatives that black people were not members of a different, inferior race but human beings like him. While he studied medicine at Edinburgh University he met his first black man, a freed slave who taught him how to stuff birds. Darwin found him intelligent and pleasant to work with. However, at the university he also encountered others who did not share his liberal views. For example, certain phrenologists were using skull sizes and their protuberances to characterize racial intelligence and temperament. Some anthropologists in the United States manipulated these results to justify slavery.

When Darwin transferred to Cambridge University to train to become an Anglican clergyman, he tended to form close relationships with those faculty members who shared his antislavery views, including John Henslow, an excellent botanist as well as an ardent abolitionist. Henslow played a pivotal role in Darwin’s getting a position aboard the Beagle. During his travels, Darwin experienced firsthand the evils of slavery in South American port cities and in the Brazilian and Argentinian countryside. The screams of brutally punished slaves and the cries of black mothers, fathers, and children who were being separated for sale created indelible memories that, the authors claim, were more significant in forming Darwin’s views on common ancestry than was his collecting of fossils and finches. Darwin was also horrified by educated people in South America, Australia, and South Africa who had convinced themselves that aboriginal populations were “pests” that needed to be eradicated.

Following his return to England in 1836, the image of a genealogical tree began to dominate Darwin’s thinking about the relationship among all branches of life, plants and animals as well as humans. Some historians of science, familiar with Darwin’s extensive researches in natural history, may question the authors’ contention that his antislavery views were the “key driver” in the formation of his theory of natural selection. Humans were certainly not the sole source of his insights. Nevertheless, Desmond and Moore make a case that Darwin’s 1838 postulation of natural selection owes much to his conviction that humans of all races constitute a single species descended from a common ancestor. Emma Wedgwood, who became his wife in 1839, was as passionately antislavery as her husband, but she derived her convictions from her Christian faith, which taught that all humans had souls infused by God. Even though Emma easily adapted to her husband’s sexismhe believed that males are naturally more courageous, intelligent, and imaginative than femalesshe was distraught as his studies in natural history transformed him from a believing Anglican to a materialist agnostic. Darwin was even gathering information to show that human religious and moral feelings were rooted in the instincts of lower animals.

As Darwin accumulated data to support his radically new ideas on “descent with modification,” he was appalled by those scientists, such as Louis Agassiz, Samuel George Morton, and Josiah Nott, who claimed to have discovered evidence that human races had separate origins in different places. Some of these scientists thought that the evidence indicated that there were two human species (black and white), while Agassiz argued for eight. Others proposed fifteen, twenty-two, and even sixty-three different human species. Morton’s Crania Americana (1839), based on measurements of many skulls, posited twenty-two great families of humans. Morton went on to hierarchize these families, using this information to justify the genocide of Native Americans and the enslavement of black Africans. Josiah Nott, a slave-owning physician, used Morton’s data in his campaign against miscegenation and for the slave system. In 1854, Nott, with George Glidden, published Types of Mankind, in which they argued for polygenism, the doctrine that humans are divided into different but fixed races, each of which had originated in specific geographical regions. Agassiz wrote the introduction for this book, which has been listed among the most prominent racist tracts in antebellum America.

Darwin was disheartened by Agassiz’s identification with the segregationist and pro-slavery group. Even such an intelligent and compassionate person as the geologist Charles Lyell, Darwin’s mentor and friend, came, after visits to the American South, to share Morton’s views. These scientists believed that black people were suitable only for servitude.

To refute those who held that human races constituted different species, Darwin collected evidence from domesticated animals, such as pigeons, which, despite their many varieties, had originated from a common ancestor. Darwin was writing a massive work on natural selection, and he intended to devote much attention to the descent of human races from a single ancestor (the unitarist, or monogenist, theory), which directly contradicted Agassiz’s polygenist, or pluralist, views. For twenty years, Darwin labored on this ever-expanding tome, but, fearing controversy, he shared his radical ideas only with close friendsuntil 1858, when the naturalist Alfred Russel Wallace sent him a scientific paper that clearly demonstrated that Wallace had independently arrived at the theory of natural selection. This paper served to end Darwin’s procrastination, and in 1859 he published On the Origin of Species by Means of Natural Selection. This work, which did not include Darwin’s ideas and data on human evolution, appeared just before the outbreak of the American Civil War.

The exclusion of humans from Darwin’s book did not prevent readers from extrapolating the consequences of his argument from plants and animals to humans. Some even used Darwin’s example of certain ant species that enslave others in their justification of human slavery, an interpretation that infuriated him, since he felt it was absurd to jump from the unreasoning, instinctual behavior of an ant species to the rational, moral behavior of a human being. Darwin closely followed the American Civil War, and he was critical of Lincoln for fighting it to preserve the Union rather than to abolish slavery. He was also critical of Lincoln’s Emancipation Proclamation, which freed slaves only in the rebel states, where the president had no direct control, and not in those Union states that permitted slavery, where he had the power to effect this change. When the war ended, Darwin confessed an error, since he had believed, along with many Englishmen, that slavery would flourish for centuries in the Southern states.

Darwin also reacted to British brutality against members of other races. When British colonial subjects in Jamaica revolted, the governor brutally repressed the rebellion, slaughtering hundreds of black Jamaicans. Darwin denounced the action, but the governor’s decision was defended, to Darwin’s chagrin, by several of his friends and even by his son William. Despite his sympathies for black people, Darwin realized that, throughout history, “civilized” races had exterminated and replaced “savage” races all over the world. Furthermore, he did not entirely escape the prejudices of the “cultural ladder” accepted by many of his racist and elitist friends and colleagues. For example, in The Descent of Man and Selection in Relation to Sex, he engaged in what today would be called ethnic stereotyping when he quoted with approval a characterization of the Irish as lazy, squalid, and licentious. When an Irish reader asked him to remove this offensive passage in later editions, he refused.

Others, such as Wallace, criticized Darwin’s emphasis on sexual selection to explain the origin of human races, but Darwin continued to defend his theory, which he hoped would resolve the dispute between monogenists and polygenists. In this he was mistaken. He was not even able to remove the taints of racism, classism, sexism, and imperialism from his own thinking and feelings.

Desmond and Moore end their account somewhat abruptly in 1871, leaving readers to wonder about the development of Darwin’s ideas on race in the remaining eleven years of his life. Because they so emphasize Darwin’s humanitarianism and enlightened thinking about slavery, some readers may be surprised, even shocked, by Darwin’s statements on the inferiority of aborigines, his denigration of the working classes, and his defense of the British colonial empire. Some scientists and historians of science have criticized the book for what they feel is the authors’ overemphasis on abolition as the source of Darwin’s revolutionary ideas. They point out that the evidence indicates that Darwin had a passion for wresting truths from the natural world that was even stronger than his moral passion against slavery. Religious critics have supported Emma’s views against her husband’s by stressing that his materialistic theory of natural selection provides no basis for a moral outrage against slavery. Slave owners, after all, could be interpreted as fighting for the survival of their way of life.

In the commemorative year of 2009, many books and discussions about Darwin and Lincoln served to bring out the complexities of their views on race, class, and colonialism. Darwin and Lincoln shared some of the racial prejudices of their contemporaries, but this did not prevent Lincoln from taking actions that eventually led to the liberation of American slaves. Darwin, despite being tied to some of the values of his gentlemanly class, was able to free scientists from false views about the origin of species while playing a not-insignificant role in the movement to free the world’s slaves.