The PhD study “A technology of well-being” takes on a positive, resource-oriented approach to the research on use of MP3 players. The aim of the study is to explore whether and how the use of MP3 players can function as a medium of musical self-care, subjective well-being, and positive health. Researching the possible role of MP3 players in individuals’ self-care, the study focuses on self-regulation and coping. The research questions are examined implementing a qualitative, empirical study. Interviews with adult urban users of MP3 players are carried out, focusing on their experiences of this use. The interviews are analysed within a theoretical framework based on health theories and positive psychology. Although there seem to be several risks related to the use of MP3 players – hearing damage, concern about traffic safety, and issues concerning isolation and the social environment – it appears that use of MP3 players also has positive consequences for users, which are presented in this book.