Oath of Fealty - Larry Niven - Bog

In the near future, Los Angeles is an all but uninhabitable war zone, racked by crime, violence, and poverty. But above the blighted city, a Utopia has arisen: Todos Santos, a thousand-foot high single-structured city. But there are those who want to see the utopia destroyed, whose answer to tomorrow's best and brightest hope is mindless violence.