Publisher's blurb [A] fanciful simulation of survival after a worldwide nuclear war. In your adventures, you may face the dangers of radiation poisoning, dangerous animals, poisoned food, and more! User summary Atom20 was written by Ray Brander and published as type-in source code in Creative Computing Vol. 5, No. 2, February 1979. Written in BASIC, it was intended for the Minnesota Educational Computing Consortium's system - but could be adapted to other flavors of BASIC.