The authors also acknowledge the contributions of the authors of Institute of Health Economics studies on health-related quality of life reviewed in this monograph. [...] The Karnofsky scale led to the development of The Index of Independence of Activities of Daily Living (Katz et al 1963) and the 1 The Importance of Measuring Health-related Quality of Life Barthel Index (Mahoney and Barthel 1965). [...] Death may be the worst health state (equals to zero) and placed at the bottom of the scale and, perfect health (equals to 100) may be placed at the top of the scale. [...] Osoba (1999) identified the usefulness of HRQL in describing health status, assisting in the management of individual patients, in the formulation of clinical policy, in evaluating the impact of new treatment and in making resource allocation decisions. [...] Clinicians related issues: From the point of view of the healthcare provider the main barriers are related to the effectiveness of the measure (what is the clinical relevance?), lack of familiarity with the results, and the difficulty of fitting it into the office ecosystem (lack of time and resources).