A children's book by O.T. Nelson, originally published in 1977. The book explores a Wild In The Streets-esque fantasy scenario in which everyone over the age of 12 dies of a mysterious virus. Anarchy ensues, and thanks to roving, Lord of the Flies-style organizations of toughs, cities become dangerous places to live. The book follows a 10-year-old named Lisa as she first tries to organize the kids on her street into a self-sustaining, defensible community, then moves them all to an old school called Glenbard when that falls through.

According to an Amazon review, the writing is a bit heavy-handedly educational, but the sheer fantasy fulfillment value of the story to kids has kept it in print. (When he was 11 or so, my older brother took the fulfillment part a step further and designed his own role-playing game around the concept of warring pre-teen strongholds defending themselves from raiders with improvised weapons. The home of us player-characters was called Glenbard, straight from the book. He did his best to keep things at least somewhat realistic and draw them out to their logical conclusion, but it got a little out of control when he let a group of us take a car across the country to try and restore our electricity by breaking into NORAD. Even at the age of eight, I had some questions about this, but gave him the benefit of the doubt.)