Heresies comprises 24 essays, originally written for the New Statesman. The heresies discussed are intellectual and cultural ones and Gray himself does not profess any religion. The essays fall into three groups: progress, terrorism, and political commentary. Gray adopts a worldviews approach in many of these essays, acknowledging similarities between belief systems of secular humanism and religion. He recognises the assumptions that lie behind secular humanism and exposes them as pale imitations of Christian doctrines.

Gray acknowledges that religion appears to be 'hard-wired in the human animal' and states that secularism is merely a substitute of one religion for another. Consequently, the militant evangelism of secular humanists is a mark of the unspoken contradictions and fragility of their beliefs.

The book does have its problems. By its nature, it is a little repetitive. One of the essays infuriated me in its advocacy of torture in combating terrorism. Nevertheless, this book will provide much food for thought, insight into the worldview that dominates our culture, and a significant analysis of the problems within secular humanism.