Across the Secular Abyss draws upon the best social-scientific evidence to understand profound religious changes occurring in advanced societies today, as previously separate fields of science converge, leaving progressively less room for faith. It finds that the positive functions of religion have been exaggerated, are declining, and are replaceable by benefits from new Transhumanist technologies; however, serious concerns are raised whether atheism is compatible with long-term survival of the human species, given falling birth rates.