Still Doing It: The Intimate Lives of Women Over SixtyStill Doing ItThe Intimate Lives of Women over SixtyBy Deirdre Fishel and Diana HoltzbergPaperback; 208 pages An informed, honest, joyous book. Younger women may well envy us. Suzanne Braun Levine, author of Inventing the Rest of Our Lives Sex, love, and life can grow even richer as we grow older, and the stereotype busting women in this book show us scores of ways. These women are not going downhill, they''re on a roll. They are women of juice and