The aim of this book is to lead the reader to reflect on two fundamental aspects of human development: aggression and intelligence. As well as detailing the constructs and their facets, this work sets out to answer the essential question: is there a relationship between levels of aggression and intelligence? The cultural imagination brings with it the idea that aggressive people or psychopaths are intelligent, cold and calculating. But how real is this idea? In order to provide a robust answer, this study used recognised and scientifically validated psychological instruments. The period of adolescence was chosen to address these issues because it is at this time that the human being undergoes profound transformations in their personality that prepare them for adulthood and these constructs are in evidence. The results provide perspectives that open up new possibilities for reflection and research for all those who are interested in or work with the topics covered.