Most aging books deal with the outer work of aging, especially how to care for your body better. Connie Zweig, in her book, "The Inner Work of Age" looks at how to care for your soul as you get older.
There are so many ways to age gracefully no matter what your outer circumstances are. It's the inner circumstances, even when related to the outer, that really count for your soul growth.
Her book is very comprehensive and examines many ways to look inward and work on the deep psyches at work in the story of your life.