In the year 2004, after the collapse of the USA, the Domed City of Atlanta forms an Urban Nucleus that is part of the Urban Federation of city-states which is trying to preserve civilization.  But the government, once relatively benign, is sliding into dictatorship.  Bizarre cults and sects develop and decay as people respond to the new realities around them.  The Septigamokians, an experiment in group living and marriage among the aged, are disbanded by the dictator.  The Glissadors, young people employed as messengers who meet for dance and exercise, are exterminated.  Religious fervor becomes intense, and even alien visitors from the stars convert to "Ortho-urban" Christianity.
[From the flyleaf of the Berkley/Putnam edition]

Dedication:
This book is for the grandparents of my children: Nora Hobeika Bishop and Lee Otis Bishop.  Minnie Ellis Whitaker and John Gregory Whitaker.  Maxine Elaine Willis and Charles Edwin Willis.  With much love, always.  (My children are luckier than most.)