A diagnosis of cancer is not an isolated event, but rather a poignant moment in an often-lengthy time-line. In some cases, that timeline begins with a set of risk behaviors that make an individual vulnerable to cancer. The next step may be a routine screening test to identify the presence of cancer, or perhaps a proactive effort by the individual to seek help in the face of emerging symptoms or warning signs, often followed by additional tests to characterize the precise nature of the cancer diagnosis. Following a diagnosis, people face treatment decisions, sometimes with the option of enrolling in a clinical trial. At each of these points in the timeline, attitudes play a role in determining both patients’ and physicians’ intentions and behavior. Patients’ attitudes toward risky and healthy behaviors contribute to the likelihood that they will become vulnerable to cancer; their attitudes toward screening tests and help seeking contribute to the likelihood of catching the cancer at an early stage (if at all); their attitudes toward various treatment options contribute to their course of treatment and ultimate prognosis; and their attitudes toward clinical trials and genetic testing contribute to the likelihood of their participation in each. Even at the point of diagnosis, physicians’, patients’, and family members’ attitudes toward disclosure of diagnostic information can contribute to the extent and type of information patients receive about their cancer. In this chapter, we review the broad and sometimes inconsistent literature on attitudes in the context of cancer, with an effort to organize this research area and identify opportunities for further progress.