Mayer admired Garrison, the most important leader of the abolitionist movement. In this book, he succeeds in renovating the reputation of a great reformer and activist who has often been neglected or written off as a crank.
Garrison and the abolitionists were originally hardly more popular in the North than in the South. They were seen as disrupting the Union and were regarded with suspicion for their pro-black beliefs - public opinion in the North was only marginally less racist than in Dixie. Garrison's courage and consistent refusal to trim his convictions for popular acceptance led to a career with an outsized share of controversy, oppobrium, and in several cases physical danger.
Some reviewers have felt the book is too long, and it is hefty. But the length is necessary for Mayer to give a full portrait, which shows not only the man, but also the era he lived in. In particular, Mayer writes extensively about abolitionism as a movement. Abolitionists, and Garrison himself, struggled with many problems - whether to compromise by supporting politicians whose platforms called for less than full abolition, evolving from a paternalist movement of mostly privileged whites to a movement in which free blacks and escaped slaves could play a meaningful role, and reconciling the pacifist leanings of many to their role in a war against slaveholders - that will be of interest to contemporary political activists. Mayer also shows how, after abolition was accomplished, former abolitionists seeking new causes worked for other advances, including the first stirrings of the women's suffrage movement.