Neither communist, nor fascist, the personalist third way was an original attempt to remedy the malaise of liberal democracies in 1930s Europe. Personalism puts the emphasis on the human person – understood to be an individual $in\; relation$ to others – as the foundation and aim of society. Yet, because of the impossibility of subjecting the human person to a systematic definition, personalism remains complex and multifaceted, to the extent that it might be best to speak of ‘personalisms’ in the plural. The various personalist movements that emerged in France in the 1930s are little known, and the current historiography in English misrepresents them. This dissertation is a study of the various personalist movements based in France in the 1930s, examining their spiritual research and political philosophy through the vantage point of Swiss writer Denis de Rougemont (1906-1985). In Rougemont lies the key to understanding the personalist groupings because he was the only thinker to remain active in the two foremost movements (Ordre Nouveau and Esprit) throughout the 1930s. The personalism of Ordre Nouveau was the most original, in both senses of the term. It deserves particular attention as an important political philosophy and an attempt to justify political and economic federalism in 1930s Europe. Whilst an Ordre Nouveau activist, Rougemont can be looked upon as the mediator and federator of personalisms in the 1930s. However, Rougemont’s particular contribution to personalist thought was more spiritual and theological than political or economic. Rougemont saw it as his vocation, in a strict religious sense, to oppose ‘totalitarian’ regimes. In the final analysis, Rougemont’s personalism was best expressed in the minor classic $L’Amour\; et\; l’Occident$ (1939). Love, as the affirmation of personal freedom and responsibility vis-à-vis other persons, is the closest illustration of what lies at the heart of the personalism of Denis de Rougemont.