Letter to a Christian Nation by Sam Harris is a short, sharply written open letter that responds to Christian critics of his earlier book The End of Faith. Harris directly challenges the intellectual and moral foundations of conservative Christianity, arguing that the Bible cannot serve as a reliable ethical guide, that faith without evidence is dangerous, and that religious dogma harms public policy on issues ranging from science education to stem-cell research.

Concise and unapologetically confrontational, the book succeeds as a clear, forceful case for secular reason, though its polemical tone will likely persuade mainly those already inclined to agree.