Pinning down Lincoln on race and slavery is as difficult for the historical profession as it was for Lincoln's political rivals. Eric Foner, whose long list of publications has focussed on the social, intellectual and political cross-currents of nineteenth-century America, now turns his attention to this trickiest of subjects. The result is an impressive, eminently readable monograph that will surely appeal to a broad audience.

Foner is candid about his aims. The Fiery Trial is intended to be “both less and more than another biography” of Lincoln (xvi). Less, in that it details only those aspects of Lincoln's life that cast light on his relationship with slavery. More, in so far as Foner aims to place Lincoln within the broad range of anti-slavery politics that existed in the mid-nineteenth-century United States; Foner skewers those historians who would seek to explain events in Lincoln's life solely by looking to the man himself rather than to the historical context of Lincoln's career. Linked with this broader endeavour is his successful demonstration that, far from being naive dreamers, abolitionists were politically savvy operators, closely attuned to the value of public opinion, who staked out political territory that Lincoln later came to occupy. Finally, as Foner rightly notes, much existing scholarship erroneously projects authenticity and consistency onto particular episodes or speeches in Lincoln's life in an effort to uncover “the real Lincoln.” The Fiery Trial eschews such an approach.

The volume is framed as a study of Lincoln's “growth” on the related subjects of slavery and race. Foner's Lincoln is not a born emancipator, biding his time for the opportunity to reveal his abolitionist schemes. Nor is he a vacuous, easily swayed politician dealing in expediency. Rather, he only slowly moves away from the gradualist anti-slavery politics of his political hero, Henry Clay, with its emphasis on compensation and black colonization outside the boundaries of the United States. Both ideas retained some hold over Lincoln well into the Civil War. Despite this, Foner shows that throughout his career Lincoln consistently espoused a moral opposition to slavery, arguing that the institution was unjust in denying slaves their natural right to self-government (as enunciated in the Declaration of Independence) and the right to the fruits of their own labour. Beyond this, however, Lincoln faced the difficulty of translating these beliefs into political action. Foner persuasively argues that the fluidity of Civil War-era politics, black military service, Lincoln's increasing contact with black Americans, and his responsiveness to new ideas and approaches whilst President contributed decisively to his eventual embrace of emancipation and some measure of black suffrage by the conflict's end.

Foner deftly outlines the shifting sands of Civil War politics, in which radical positions became conservative orthodoxy with startling speed. Lincoln's attitude to emancipation was intimately bound up with his conception of the US constitution and, especially, his strong and enduring faith in southern unionism: only with the failure of compensated emancipation schemes for the border states did Lincoln embrace the more radical alternative of the Emancipation Proclamation. Foner is also convincing in separating out the issues of race and slavery, arguing that though Lincoln had long pondered the iniquities of the peculiar institution, he had given little thought to what a post-emancipation United States might look like. In particular, Foner highlights the contrast between Lincoln's firm opposition to the institution of slavery – a violation of the natural rights of men and women – and his anaemic account of civil rights in a profoundly racist society. Indeed, this is a thread that runs through the heart of The Fiery Trial, from Lincoln's debates with Douglas in 1858 through his plans for Reconstruction near the war's end.

In framing his account in terms of Lincoln's intellectual and political growth on questions of race and slavery, Foner replicates the approach of numerous recent historians, not least those contained in the Foner-edited volume Our Lincoln (2008). In his introduction, he ponders the qualifications of such an approach, but one wonders whether it masks more than it explains. This reader, at least, was struck not so much by Lincoln's growth, around which there now exists something approaching historical consensus, as by the tenacity with which he continued to cling to ideas after they had become politically dubious. This is true, for instance, of Foner's exposition of Lincoln's faith in southern unionism as the political scaffolding with which the nation might be reconstructed, and also of the hold that the British example of West Indian emancipation and apprenticeship exercised over Lincoln (despite the widely publicized flaws of that plan). One also wonders how new research detailing Lincoln's obdurate commitment to colonization after 1863 – a subject to which Foner alludes in a footnote – might further complicate our ideas about Lincoln's growth.

This, though, is a fine study, and one that deserves a wide readership. What emerges with great clarity is just how uncertain politics became during the Civil War, in which the constant need to build and sustain political coalitions cut against protean ideas about emancipation and citizenship. In addition, Foner's decision to relegate historiographical contention to the endnotes leaves a central text which is tight, lucid, and clearly argued. The Fiery Trial will undoubtedly command the attention of both scholars and non-scholars alike who wish to better understand Abraham Lincoln and his complex relationship with race and slavery.