In the first half of the 20th century, the reputation of American Catholics was not so good. Didn't the novelist Flannery O'Connor write that their main concern was to "install central heating in holy places"? This book reveals a little-known page in the intellectual history of American Catholicism, and shows another face of transatlantic relations. "It is in the order of spirit and culture that the Atlantic community assumes its most fundamental historical importance", as Jacques Maritain noted. Before many European intellectuals found themselves in exile in New York between 1940 and 1945, and long before the influence of "French Theory" in the United States, Jacques Maritain, Étienne Gilson, Father Marie-Dominique Chenu, Charles De Koninck and Yves Simon taught in North America between the wars and founded institutes in Toronto, Notre Dame, Laval, Princeton, destined to play a decisive role in the intellectual mutations of North American Catholicism and beyond. To trace the history of these philosophers, Florian Michel had access to archives in France, Italy, the USA and Canada.