In this book the author introduces in the literature of personnel selection the sociological approach. This is one of the main novelties of this book. As in other fields of study on the interactive dynamics between socioeconomic actors, the sociological approach fits well between the traditional economic and psychologic literature. To fulfil this objective, the analytical framework for this book is based on the main sociological contributions (classical and contemporary) on the mechanisms of action at both the micro and the macro level, compared and integrated with the most well-known economic and psychological theories. Moreover, this book includes data from simulation experiments of the selection process that were implemented by the author, along with data on this phenomenon that were collected through some international surveys. To reiterate, the aim of this project is to understand the phenomenon as much as possible in its entirety, both in theoretical and in scientific terms, trying to integrate internal validity with external validity. A second important novelty of this book, along with the sociological approach, concerns the presence of in-depth studies (the boxes in each chapter) and exercises (in the mylab platform) created specifically for the book by two professionals who have been working in the field of personnel selection at the international level for many years and who have decades of experience in staff training: Enza Artino and Giancarlo Pozzoli.