This report supplements a prior report--Civil Defense Rescue Requirements Following a Nuclear Attack--and provides the results of extended study of four subject areas contained in that report: (1) the "trapping function", the probable number of persons to be trapped in debris; (2) the relationship between thermal effects and rescue feasibility; (3) the organizational requirements and other criteria on detection of existence of life within debris. The four research areas are treated separately, but integrated within a common introduction and summary.