In the early Americas, women and men tolerated many types of contradiction: philosophical, political, legal, financial, spiritual and cultural. In Rachel Walker's Beauty and the Brain, the author explores just one of these contradictions – that the United States was founded on ideals and ideologies of egalitarianism, but that it protected and promoted gross inequalities of all kinds – through study of the popular sciences of phrenology and physiognomy. Walker shows with skill and insight how early American people deployed these sciences to enforce pre-existing hierarchies and, sometimes, to challenge them.

Walker traces the popularity of these scientific disciplines in the new United States from the middle of the eighteenth century through to the middle of the nineteenth. In this hundred-year period, what started as a cutting-edge science practised by elite women and men became, over time, a distinctive popular science, advanced and promoted by people from many walks of life. Phrenology and physiognomy were marked by malleability and adaptability, and American women and men who were marginalized, disenfranchised and forced into positions of inequality were able to find flexibility in its sometimes perplexing doctrines. It was, as Walker argues, ‘the inherent instability and lack of systemic methodology of these sciences’ which allowed them to become so important and enduring (p. 175).

Walker makes clear that these disciplines were, in fact, exceptionally important. The book begins in pre-Revolutionary North America, where figures such as Abigail and John Adams, Benjamin Rush and Charles Willson Peale turned to physiognomy, the study of facial features and expressions, to justify their political and cultural beliefs. Privileging the white skin, long noses and broad foreheads that they believed were characteristic of elite people of English descent, these influential women and men found what they believed were scientific justifications for their own superiority. Walker describes the popularity and influence of Johann Kasper Lavater's Essays on Physiognomy, finding evidence of his theories in the public and private writings of the founding mothers and fathers of the United States. Desperate, particularly in the post-Revolutionary years, to shore up their international reputations as sophisticated, reasonable and intellectual people, these elite Americans touted Lavater's works and argued that the new nation's leaders, most especially George Washington, possessed faces and bodies marked by greatness.

The next two chapters, ‘A new science of man’ and ‘Character detectives’, introduce phrenology, which focused on analysis of the skull, and also work to demonstrate how both disciplines came to dominate the popular imagination. While elite thinkers had championed these sciences in the eighteenth century, by the first few decades of the nineteenth century, white physicians, lawyers and intellectuals began to distance themselves from the doctrines. But physiognomy and phrenology became increasingly popular with seemingly every other American. Members of the public rushed to attend phrenology workshops, visit phrenological museums, and dig their fingers into the heads and hair of their friends and family, all to learn about their supposedly inherent traits and impulses. These now-popular sciences seemed to offer everyday people the chance to better understand and appreciate themselves, and this was surely part of the appeal. But as Walker shows so deftly, it also gave them the excuse to belittle and castigate others. We see how physiognomy and phrenology were used to justify the genocide of Indigenous people – particularly during the Second Seminole War, where Native remains were purposefully desecrated and stolen for placement in phrenological museums – and to deny voting rights to white women and Black women and men. The racist, classist and sexist beliefs that had long been a part of the United States’ intellectual and cultural landscape were given new power through physiognomy and phrenology.

The book hits its stride in the brilliant Chapter 4, ‘The manly brow movement’, which shows how popular science influenced popular fashion. The distinctive women's hairstyles so popular in the 1830s and 1840s, with hair parted severely down the centre of the head and also from ear to ear, pulled tightly to the skull, and looped around the bottom of the purposefully exposed ears – a style worn by Queen Victoria, Margaret Fuller, Marie Anna of Bavaria and many others – was designed to draw attention to the wide, high, exposed brow and reinforced phrenological beliefs about intelligence and the human forehead. When women wore these literally highbrow styles, they were praised for their intellect and sensitivity. And, as Walker demonstrates, many women worked to achieve these characteristics not just through styling, but through strategic use of depilatories, waxing, shaving and plucking, with often dire results. This type of analysis, in which insights from the history of science are brought to bear on studies of gender, sexuality, beauty and popular culture, is a true highlight of the book.

The final two chapters, on ‘Criminal minds’ and ‘Facing race’, are equally well conceived. Walker argues that popular adoption of physiognomy and phrenology, particularly by white, first-wave feminists and Black intellectuals, was illustrative of the ways in which these flexible, perplexing sciences could work. Striving to show how people could be ‘improved’ by hard work, education and political voice, these women and men used physiognomy and phrenology to argue that education could provoke osteological changes in the skulls of children. The very things that made physiognomy and phrenology ambiguous also made them adaptable, accessible and accommodating. Black writers in particular seized upon this, using facial analysis to prove their deserved place in American society. As Walker shows so convincingly, while physiognomy and phrenology were repeatedly and habitually used to privilege white, elite masculinity, the disciplines were also employed, strategically and purposefully, by the very people they often denigrated. This is precisely the kind of contradiction that so frequently shaped and marked the early Americas.