This study examines methods of determining blast shelter deployments and of assessing their performance for a variety of nuclear attack. The goal is not to seek a single optimal deployment, which generally requires making arbitrary assumptions on the nature and size of the attack, thus overlooking the attacker's freedom of choice after a blast shelter program has been deployed. Rather, the study seeks "stabilized" deployments which protect population almost as well as an optimal deployment, even though it is not truly optimal for any specified attack. The study examines the attacker's freedom to vary force level, time of attack, attack objective, height of burst, and targeting. A quite general and flexible computer model BLAST, based on generalized Lagrange multipliers, generates shelter deployments for the U.S. and computes their eftectiveness against attacks in which these factors are varied. In BLAST the nation is considered as a collection of cells two nautical miles square, providing a detailed analysis of the offense/defense interaction. Volume I summarizes the methodology, results, and conclusions. Volume II contains technical appendixes, including the data employed. Volume III describes BLAST in detail for the analyst and programmer.