Triplanetary (1934, SERIALIZED version) is a science fiction novel and space opera by American author E. E. 'Doc' Smith. It was first serialized in the magazine Amazing Stories in 1934.
The novel covers several episodes in an eons-long human breeding project by the super-intelligences of the Arisians. This alien race is breeding two genetic lines to become the ultimate weapon in Arisia's cosmic war with their arch-enemies, the Eddorians.