The updated version of Diario della Salute (DDS-2) is a universal school-based intervention aimed at promoting psychological and emotional well-being and preventing unhealthy and risky behaviours (cigarettes smoking, alcohol abuse, unhealthy eating habits, physical inactivity) in preadolescence. The program is composed by 5 highly standardized interactive units delivered by previously trained teachers during school hours on emotional and social issues related to developmental tasks in adolescence. The kit includes: 1) a teacher's manual, 2) a booklet for each participating student, 3) a booklet for parents of each participating student. The objective is to promote and reinforce adolescents' emotional and social skills as factors contributing to adolescent well-being and health.