The purpose of this chapter is to provide a guide to the signs and symptoms of a major depressive disorder. Use the information in this chapter to help identify signs of depression which you may be experiencing and to help you take charge of your illness and formulate the best treatment plan. A case study is provided that illustrates depression related to ‘job burn-out’; and the causes of depression are outlined, as well as a symptom checklist. The diagnostic criteria of depression are outlined as are various treatment modalities and the differences among various treatment providers.