The effects of weightlessness on small living organisms, and methods for improving biological techniques were investigated in the seven experiments reported in this pamphlet which is intended as a curriculum supplement for secondary schools. Topics include: (1) killfish hatching and orientation; (2) microbial growth and changes in biorhythm; (3) cell separation by electrophoresis; (4) microbial exchange in the space raft; and (5) changes in astronaut immunity during spaceflight. The pamphlet is intended as a curriculum supplement for secondary schools