• Social-psychological aging is framed as life review, evolving identity, morale, social networks, attitudes toward older people, and the elder's social world shaping well-being and care [1][8][11][18][15][10][20].

• Leisure, recreation, and sustained activity are central to aging well, linking leisure time use and active lifestyles to morale and perceived quality of life across the elderly [14][13][8][20].

• Biological aging mechanisms and theory: papers on free radical aging, biological aging mechanisms, and a composite theory integrate biology with epidemiology and social science [19][7][5].

• Clinical aging and health services: operative mortality risk, geriatric institutional management, and social loss around dying patients illustrate aging as a health system and care delivery issue [2][17][10].

• Cognitive and perceptual aging: studies on reaction time and subjective speed of time show aging-related changes in processing and temporal perception [9][16].