Triplanetary by E. E. Smith - is a science fiction novel and space opera by American writer E. E. Smith. It was first serialized in the magazine Amazing Stories in 1934. After the original four novels of the Lensman series were published, Smith expanded and reworked Triplanetary into the first of two prequels for the series. The fix-up novel Triplanetary was published in book form in 1948 by Fantasy Press. The second prequel, First Lensman, was a new original novel published in 1950 by Fantasy Press.
Triplanetary is a prologue to the Lensman series. It consists of two parts. The first explains the series background, which consists of a conflict between the evil Eddorians and the benevolent Arisians. This conflict is carried out throughout the history of an oblivious humankind on Earth. The Arisians undertake a eugenics project to breed two human genetic lines that are intended to become the ultimate weapon in Arisia's cosmic war with Eddore.
The author takes five defining chapters to cover the background of the Kinnison line: the destruction of Atlantis in a nuclear war, an attempted coup in Rome against the Eddorian-controlled Nero, the First and Second World Wars, and, finally, a nuclear Third World War. In each of these periods he tells part of the story of the two families who will be of importance later on, and who will produce the two people whose children will be the culmination of the human breeding line, Kimball Kinnison and Clarissa MacDougall. One genetic line is surnamed "Kinnison" or some close variation. The other line is distinguished by having "red-bronze-auburn hair" and unusually colored "gold-flecked, tawny eyes".
The final part of the book, which was originally published as a magazine story, takes up the tale after civilization has been rebuilt with the covert help of the Arisians. Humanity has explored the Solar System and formed the Triplanetary League, which consists of an alliance of Earth with the governments of Mars and Venus. Prior to the start of the main story, humans have set up in-system colonies and fought the first interplanetary war against the Adepts of North Polar Jupiter.
As the story begins, interplanetary commerce is plagued by pirates. The fleet of these pirates is led by Gray Roger, a surviving Adept of North Polar Jupiter. Unbeknownst to the Patrol, Gray Roger is actually Gharlane of Eddore. The pirate fleet and the Triplanetary Patrol are in the midst of a large-scale engagement when an alien race known as the Nevians show up. The Nevians are the dominant, amphibious race of the planet Nevia, located many light years distant from the Sun. Their planet is in a galactic region that has very little iron, which they use as an energy source, so they set out with a spaceship to try to obtain more.