This chapter provides the reader with an understanding of the importance of clinical and health services delivery research among older adults. It highlights the importance of an interdisciplinary approach to clinical and healthcare delivery research. The chapter also discusses issues that have been identified by the Task Force on Aging as being among those "most important", having immediate priority. Broad categories of clinical or patient-oriented research include: investigation of the pathophysiology of aging; the identification of at-risk and special populations; the classification and diagnosis of specific conditions and diseases; and the evaluation of preventive and therapeutic interventions. The identification of existing diseases and/or conditions and assessing individual risk factors allows application of appropriate and effective interventions which then must be evaluated. Aging is the most prominent risk factor in Alzheimer's disease, and many research efforts are directed to discovering the linkages between the aging process and this particular form of dementia.