Choosing a career is one of the most important decisions that a person has to make, and the first step in this process takes place in adolescence. In this book you will find an entire intervention program designed to help teenagers make effective career decisions and successfully overcome the inherent difficulties of this process.The first chapter of this book presents the theoretical basis of the KCC ('I Know! I Can! I Choose!') intervention program, information carefully synthesized after a thorough analysis of the theories in the field of career counselling.The second chapter of the paper describes in detail the testing of the effectiveness of the KCC intervention program, the research methodology and the statistical procedures involved. The final chapter of the paper is by far the most valuable part as it details the component activities of the KCC career choice intervention program. Teachers, career counsellors, and all professionals in this field will be able to consult valuable resources that can be useful in supporting their students in making inspired decisions regarding their future careers.