This flawed but useful book on the influence of the Progressive movement in U.S. history illustrates both the potential and the limits of sentimental radicalism as a force in U.S. historiography. McGerr has a clear preference for radicals over Progressive middle-class leaders such as Jane Addams and Theodore Roosevelt, which gives him a better understanding of the limits of Progressivism than more conventionally liberal historians. Many historians of Progressivism have reluctantly acknowledged the popularity of eugenics and immigration restrictions among their subjects; McGerr goes further, illuminating the role Progressives played in establishing and then defending segregation and the degree to which they attempted to coercively reform the lower classes. Yet McGerr's nostalgic (and very middle class) radicalism creates blind spots of its own. In particular, by limiting his serious political analysis of Progressive thought to the early years of the period, he underestimates the radicalism that increasingly shaped Progressive leaders such as Theodore Roosevelt after 1910. One is left thinking that Mark Twain's description of the Widow Douglass, who wanted to "sivilize" Huck Finn and his father, is the best account of American Progressivism -- and that Twain's description of Huck "lighting out for the territories" to escape the shackles of her well-intentioned rules remains the best description of why the Mugwumps, prohibitionists, earnest professors, food cranks, suffragettes, segregationists, social workers, and missionaries of Progressive America never quite got their way.