The goal of clinical diagnosis in traditional medicine is identification of the disease process and formulation of a plan to treat the disease. When psychosocial factors are added to the medical symptomatology, the patient cannot be seen simply as a vessel who carries a group of predictable or constant symptoms available for evaluation. Rather, psychosocial events and the patient's premorbid personality covary to create a changing constellation. Under these circumstances, clinical analysis must not only systematically evaluate these varied elements, but it must also elucidate their interrelationships and dynamic flow. Current behaviors and attitudes should be interpreted in conjunction with the physical aspects of the presenting problem. The premorbid background of the patient must be delineated in an effort to clarify the historical context or pattern of the syndrome. Moreover, personality and environmental circumstances must be appraised to optimize therapeutic recommendations. Ultimately, the goal of psychological assessment is the development of a preventive or remedial plan.It is now well established that pain, along with most medical conditions, is profoundly influenced by psychological factors. Descartes' dualism-that mind and body are separate-is increasingly seen as an untenable philosophical underpinning for understanding and treating medical problems. Clinical psychological analysis with medical patients is both an abbreviated and a more extensive evaluation than for the psychiatric patient, as characterized by Millon (1969). The first task is the description of the clinical picture. The presenting medical problem is often the most obvious aspect, but it often serves as a precipitant of difficulties of a more extensive or long-lasting nature. The physical problem must be evaluated for its effects on the physiology of the individual and for its influence on the emotions of the patient and those who surround the patient. Thus, it is important to evaluate the individual's overt behaviors, stated reports of feelings along with the inferred intrapsychic processes, and biophysical processes.This chapter introduces two scales that have been used to assess personality: the