Serious, chronic disease, such as sarcoidosis, evokes life-changes that may require mastering stress, recovering self-esteem and finding alternative sources of satisfaction for what is lost. 2. The theory of mastery offers patients and nurses an explanation of how to emerge ever stronger and more resilient in dealing with the self and the environment. 3. Over time, four stages of the theory of mastery may be encountered: certainty, change, acceptance, and growth. Nurses may assist patients to see how they may "master" each stage to achieve personal growth, hence a greater quality of life.