Arts applications for health – whether for clinical treatment or its complement in health promotion – tend to be “canalized”: research and practice in one art domain tend to be done in isolation from research and practice in other art domains. As a result, arts applications for health lack a unifying theoretical framework that would allow for the rational selection and inclusion of the arts into programs of health. In this thesis, I present two theoretical articles that address this problem. The first article, Toward a New Science of the Clinical Uses of the Arts, proposes a framework unifying clinical arts applications. It argues for the equivalence of psychotherapies (whether arts-based or not) in treating mental illness because all psychotherapies rely on the same set of common therapeutic factors in producing their clinical effects. In contrast, we argue for the non-equivalence (i.e., the specificity) of physical therapies (whether arts-based or not) in treating physical illness since physical therapies rely on specific therapeutic factors unique to each therapy in producing most of their clinical effects. The second article, Toward a Unification of Arts Applications for Health Promotion, proposes a framework for unifying the arts as leisure activities for health promotion. I propose that all leisure activities (whether arts-based or not) rely on a set of five common health-promoting factors in producing their effects. This results in an equivalence of outcomes when any two leisure activities possess the same health-promoting factors. Arts applications for both clinical treatment and health promotion show similarities in that both operate via “transfer effects,” whereby the arts transfer benefits to non-arts health domains. The arts tend to improve mental health via “far” transfer effects, whereas they tend to improve physical health via “near” transfer effects. / Thesis / Master of Science (MSc) / Arts applications for health – whether for clinical treatment or its complement in health promotion – tend to be “canalized”: research and practice in one art domain tend to be done in isolation from research and practice in other art domains. As a result, arts applications for health lack a unifying theoretical framework that would allow for the rational selection and inclusion of the arts into programs of health. I present two theoretical articles that address this problem. The first, Toward a New Science of the Clinical Uses of the Arts, proposes a framework for unifying the clinical applications of the arts. The second, Toward a Unification of Arts Applications for Health Promotion, proposes a framework unifying the arts as leisure activities for health promotion. Arts applications for both clinical treatment and health promotion operate via “transfer effects,” whereby the arts transfer benefits to non-arts health domains.