At first glance it appears that little has happened in our understanding of bronchogenic carcinoma, since five year survival rates have not changed appreciably over the past ten years. This is partially true, however the depth of our understanding has increased and will continue to do so at a rapid pace over the next five to ten years. Information on the basic tumor biology, identification of important groups at high risk and im proved delivery of cytotoxic agents in the treatment of lung cancer, will all add to improve the outcome. The purpose of this text is to provide useful background information and to serve as a reference for approaching the patient with lung cancer. Therefore it will serve as a review for some and as a beginning for others. An important starting point in any discussion of lung cancer is an epidemiological survey of the topic (Chapter I). For those who do not avoid the hazards and present with symptoms, what is the most logical approach in determining the diagnosis (Chapter II). This chapter is intended to provide a general overview of the subjects covered in detail in the remainder of the text.