Kindred Spirits takes us inside a remarkable network of Catholic historians, theologians, poets, and activists who pushed against both the far-right surge in interwar Europe and the secularizing tendencies of the leftist movements active in the early to mid-twentieth century. With meticulous attention to the complexity of real lives, Brenna Moore explores how this group sought a middle way anchored in “spiritual friendship”—religiously meaningful friendship understood as uniquely capable of facing social and political challenges. For this group, spiritual friendship was inseparable from resistance to European xenophobia and nationalism, anti-racist activism in the United States, and solidarity with Muslims during the Algerian War. Friendship, they believed, was a key to both divine and human realms, a means of accessing the transcendent while also engaging with our social and political existence. Some of the figures are still well known—philosopher Jacques Maritain, Nobel Prize laureate Gabriela Mistral, influential Islamicist Louis Massignon, poet of the Harlem renaissance Claude McKay—while others have unjustly faded from memory. Much more than an idealized portrait of a remarkable group of Catholic intellectuals from the past, Kindred Spirits is a compelling exploration of both the beauty and flaws of a vibrant social network worth remembering.