Young teenager’s early sf series of excellent stories by top- notch sf writers. Wollheim’s book focuses on the dangers realized by only one scientist once deep- core mining has begun on the moon. The scientist and his teenage son face dangers of all kinds in order to save mankind. Highly realistic in its detail, this is “ a space yarn that you won’t put down.” Book is in very good condition considering its age and has a child’s name on a blank interior page plus part of the original flap page from the cover taped inside the first page.