The sheer daunting quantity of Upton Sinclair's oeuvre has created a need for a guide through his works and this has now been met by Anthony Arthur's new biography Radical Innocent. The near paradox in his title is explained by the fact that Sinclair seems to have preserved a simple, rather moralistic view of the world despite his constant discovery of corruption. One of his favourite works was The Pilgrim's Progress and he secularized that work into a lifelong campaign to expose the tension between idealism and materialism in American life. Sinclair thus cast himself in the role of the nation's conscience. Not surprisingly, this role brought him into conflict with the great and the good, figures like Theodore Roosevelt and John D. Rockefeller.

The Jungle marked a turning point in Sinclair's fortune because here he found his subject and method: the use of fiction as a medium for exposing abuses within American commerce. Anthony Arthur identifies a recurring pattern in Sinclair's fiction of an innocent young man – obviously a surrogate for Sinclair – being converted to radicalism by the abuses he encounters. His model was Uncle Tom's Cabin, which he aimed to reproduce through engagement with contemporary social problems. His ultimate aim appears to have been to construct an epic sequence, only realized later in his career with the Lanny Budd series.

Radical Innocent presents an admirably detailed account of Sinclair's range of interests. His utopian hopes led him to establish the Home Colony in New Jersey, modelled on Charlotte Perkins Gilman's writing. Social concerns which he addressed in print included sexually transmitted disease, alcoholism, telepathy and the culture of celebrities, to name but a few. His innocence over political and monetary matters came out strongly in the 1930s, when his campaign for the governorship of California failed after bogus newsreels implied that the state would be flooded with poor migrants. Sinclair's other failure, though not a complete one, was to back Eisenstein in making the film Que Viva Mexico!. Eisenstein's extravagance and the general lack of professional organization in the project meant that ultimately only a selection of silent sequences could be salvaged. These were shown under the title Thunder Over Mexico. Arthur has drawn on a wealth of unpublished archives to document the violent fluctuations in Sinclair's private life and to fill out his portrait generally. Radical Innocent will clearly remain the standard biography for the foreseeable future.