The landscape of the world population is changing, and over recent decades in the United States the shifting demographics are manifest. Readiness, as indicated by awareness, policy and systems is developing. We appreciate that health care systems serving elders will be affected by these shifts, with optimal systems anticipating and creating triage and care systems that are responsive and effective. However, we are aware that much remains to be done to prepare for changes in referral patterns and care needs that will come. In this volume, we focus on dimensions of psychological aging associated with risk, namely the aging central nervous system and mental health of older adults. It is our hope to offer a general introduction to central matters of importance in the care of older adults at this point in the 21st century.