Mary P. Follett (1868-1933) has been considered as a pioneer in management although her contributions have been eclipsed for a long time. She contributed to give some philosophical foundations to modern theories of management. Our research follows two objectives. It aims to highlight the nature and origin of the concepts and ideas she offered. More generally, it also aims to contribute to explain the genealogy and birth of management ideas. We focus our work on one of the pillars of the conceptual edifice of Follett: the concept of integration. From a systematic and comprehensive textual analysis of books by Follett and lectures she gave to figures from the business world of her time, we highlight three results: (1) the concept of integration is produced through a process of gradual labeling; (2) Follett deliberately maintains a high degree of pragmatic ambiguity to support her reasoning; (3) she systematically demonstrates the lack of autonomy of the field of management in relation to others (political science, social psychology, etc.) in order to give value to management ideas.