The (re)publication in the Bibliothèque Idéale des Sciences Sociales (Bi2S) of the work of Georges Liénard and Émile Servais finally brings to the attention of the scientific community an unjustly unknown investigation.The new preface by Stéphane Bonnéry, underline its precursory character for the sociology of education and children.

Groups and individuals often dislike being "placed into a box". But how to approach these processes with the tools of contemporary social sciences? This lexicon proposes a toolbox of categorization processes in 48 notes.it shows the way researchers in social sciences and humanities make use of these concepts, with current illustrations of them.