For two decades, social scientists seem to be rediscovering Tarde after having “forgotten” him throughout the twentieth century. Sociology, social psychology, philosophy and criminology are emerging as the exclusive favorite fields by which to address Gabriel Tarde's thought, risking understanding him from a single “discipline” point of view—not yet existing disciplines as such in the late nineteenth century. While Gabriel Tarde's thought tends to be exploited by academic quarrels against structuralism and reduced to its conflict with Durkheim—to the point that Mucchielli (2000) spoke of “tardomania” when the new edition of Tarde's complete works was published—Tarde's collections (manuscripts and library) reveal a contradiction between the character through his archives and the character through his legacy.

But Gabriel Tarde goes well beyond controversy.

Both the manuscript collections and the library collections invite reconsideration of the published work. They highlight the process of scientific work upstream of the printed end product. According to Tarde's principle, the whole is different from the sum of its parts, each part—however small it may be—exists in itself while participating in a whole. Following Tarde, the infraordinary, the infinitesimal, the Monad, is significant in itself. In the human sciences, this rehabilitation of the small ordinary has been already experienced since Georges Perec (1989), in literature up to Carlo Ginzburg (1980) or Alain Corbin (1998) in history. Making this raw material significant, revealing the document as a source makes us refer to multiple traces of life as many completed or aborted possibles.

Tarde's collections (manuscripts and library) retrace the route from his earliest writings in Sarlat in 1860 until his death in 1904 in Paris, doing so through very dense and diverse documentary material: books and reading notes, manuscripts, poems and plays, diaries, correspondence, manuscripts of articles and books.

This documentary material, such a real library with printed and handwritten materials, plunges us into an archeology of Tarde's thought from his early readings and writings to its classification, proofreading and rewriting practices at the genesis of his works. Serving the enunciation of his thought system, Tarde established a classification system and a working method that are proving to be a real database, a “cerveau extérieur.”