This biography investigates the complex and often contradictory relationship between John Stuart Mill’s public secularism and his private engagement with religious and spiritual concepts. Timothy Larsen, a professor of Christian thought, utilizes archival research and Mill’s own writings to challenge the conventional narrative of Mill as a purely secular thinker. The book argues that Mill’s intellectual development was deeply influenced by religious contexts and that he maintained a nuanced, albeit non-traditional, openness to spiritual inquiry throughout his life.

Scholars and reviewers note that this work provides a corrective to the common perception of Mill as a staunch atheist. Experts highlight the book's meticulous use of primary sources to reveal the intellectual depth of Mill's private spiritual reflections.