social conflicts at the time of the Popular Front (1936–38). Demangeon's daughter Suzanne married the geographer Aimé Vincent Perpillou (1902–76), who also became a distinguished economic geographer. Albert Demangeon died on 25 July 1940 in Paris, France. Work Demangeon was a prolific author. His pre-war work focused on physical regional geography, but later he also wrote on larger topics including several volumes of the Géographie Universelle published under the direction of Paul Vidal de La Blache and Lucien Gallois. At the Sorbonne he turned from physical to human geography. He avoided theoretical work, and did not write a book about the general subject of human geography, although his writings on the subject were published after his death in Problems of Human Geography (1942). This collection of his main articles covered a broad spectrum of human geography topics. Demangeon was interested in the interactions of man and nature, and also in history, although he felt that geography must remain a distinct subject. He wrote in 1906, "To explain the geographical phenomena of which man has been the witness or contriver, it is necessary to study their evolution in the past with the aid of documents." Later he defined three principles for the study of human geography: It should avoid determinism. Causes are always complex and involve human initiative and choice. It should be based upon a territorial unit. To understand and describe regional units is one of the main objectives of geographical study. It must consider not only the present day. The idea of age and of evolution is indispensable. Without it, the reason for what exists often escapes us. Demangeon's 1905 study of Picardy had a strong historical element, reflecting Vidal de la Blache's emphasis on the role of man in changing the face of the earth. Also in 1905 he produced a valuable guide to the National Archives for the use of geographers. He cooperated with historians, and coauthored The Rhine, Problems of History and Economy (1935) with Lucien Febvre. He studied current issues such as colonialism, globalization, the Great Depression and German ambitions. His Le déclin de l'Europe (1920) was published in the US in 1921 under the title America and the Race for World Domination. It argued that Europe was deeply in debt and exhausted by the war, with reduced agricultural and industrial output, and low birth rates. The US and Japan had expanded their industries, replaced