The approach taken in this important biography of a very important but woefully understudied eighteenth-century American reformer, Anthony Benezet, Philadelphia Quaker and early abolitionist, is made clear early on. Benezet, Jackson claims, quoting Garry Wills, was an “American Saint.” Jackson's book is a celebration of the life of this quite extraordinary and little-appreciated humanitarian. The praise for Benezet, however, is appropriate. Benezet probably was a saint. Certainly he was a pioneering thinker, one of the very first men to get beyond ideas of Africans as savages in order to argue that these were real people. The moral argument against slavery may have been won earlier in the century, with Montesquieu and others proclaiming against the institution, but it took devout Quakers like John Woolman and Benezet to turn theory into practice. One would call this vegetarian humanist a zealot if doing so did not contradict a general sense of Benezet as the gentlest of men and among the most disinterested observers of the human condition.

Jackson does signal service in this intellectual biography in placing Benezet in a wide milieu of transatlantic thinkers in France, Britain and America. Benezet's arguments were not the most original of his day and he was the least impressive thinker of the celebrated trio that also included Franklin and Benjamin Rush who did so much to kick-start the transatlantic movement for abolition of the slave trade. But he was the most determined opponent of the slave trade of anyone save perhaps Granville Sharp – his contemporary in Britain and a man who exemplified many of the virtues that made Benezet so important. Benezet was brave in his opposition to Quaker authority, was persistent in his message that slavery was an evil that God-loving people could not entertain, and was remarkably broad-minded in his willingness to entertain notions of black intellectual and moral capacity. Jackson's book is a welcome rehabilitation of a man whom Philadelphia blacks at his death rightly acclaimed as one of the greatest friends of Africans and African Americans in American history.

What is especially interesting about Jackson's biography of Benezet is that it reflects a new and applaudable trend of taking the religious views of early abolitionists seriously. As Christopher Brown has shown in more analytical detail for British abolitionists and as Geoffrey Plank is doing for Benezet's predecessor, John Woolman, what motivated these godly men to take on one of the mightiest and most economically important institutions in the British Empire was a sense that a nation that allowed the slave trade to flourish was a nation steeped in sin. Jackson does not do much analysis in this book – the text is heavy on description and light on wider contexts. Nevertheless, his book is a welcome contribution to a growing reassessment of early abolitionism that stresses its religious roots and its transatlantic dimensions. The one thing missing from Jackson's account is the role of political contingency. What the American Revolution did in galvanizing abolitionists in Britain, the Seven Years War did a generation earlier for abolitionists in Philadelphia. Benezet was not very political. But he took advantage of a mood in Philadelphia during the Seven Years War that caused people like Franklin to reevaluate all aspects of the imperial relationship in order to advance what would have been a few years before very radical ideas about African capacity. It is a shame that more of the political context of abolition in Philadelphia is not in this book. But this is a small quibble. Let This Voice Be Heard is a terrific book about a truly great American.