Persons living with DUD are more likely than those with single mental health and substance abuse related diagnosis to have a poor quality of life and a low level of functioning in everyday life. They are often referred to as "complex" and"difficult to help", and there are documented inaccessible and unavailable tailored service systems. Persons living with DUD have typically fallen between, or been bounced, back and forth between different systems of care. In order to abate fragmented services, a comprehensive, integrated service approach has been recommended. The municipalities and the professional practitioners at the local level has by laws and regulationsgot new tasks towards persons living with long-term and complex needs. At this level, there is an increasing support for recovery-oriented rehabilitation aiming at improved quality of life and everyday life, including environmentalrestorativeness. We derived our research focus by identifying the resent knowledge base of dual recovery. The main research strategy in this project is based on action researchmethodology, with use of a mixed method design combining a qualitative component applying a co-operative inquiry and a quantitative component applying relevant questionnaires. This approach is deemed appropriate, as the objective is to develop and evaluate the principles and practices of recovery-oriented rehabilitation within the mental health and substance abuse services from various perspectives, and to develop/compare newknowledge/model about the meaning of recovery-oriented rehabilitation and quality of life for people living with dual diagnosis. As in our three earlier NRC research projects, acompetence group will be established to work with the research team in all stages of the research. The competence group will consist of service users and professionals. Inspired by the concept of participatory research, this group will participate in developing the research project in detail.