Before Dr. Lindberg wrote her thesis she had worked as a nurse for eighteen years. Over the years she encountered many patients suffering from various chronic diseases, and sometimes experienced a feeling of resignation. It was obvious for her that the situation for these persons was problematic, especially with respect to management, treatment, understanding, and obtaining objective knowledge about their disease. When Dr. Lindberg had the opportunity in 1994 to establish an asthma nurse practice (ANP) in primary health care, this represented a challenge. At that time she had not thought about this endeavour leading to a thesis, and the work that resulted in paper I in the present thesis got underway due to her curiosity about the clinical situation, i.e. she wanted to determine if an ANP was of any benefit to patients in primary health care and their families and to the health care sector. This thesis has also been written for readers who are not a part of the medical professions, such as health care users and health care planners.