The star Mira was unpredictably variable. Sometimes it was blazing, brilliant and hot. Other times it was oddly dim, cool, shedding little warmth on its many planets. Gresth Gkae, leader of the Mirans, was seeking a better star, one to which his "people" could migrate. That star had to be steady, reliable, with a good planetary system. And in his astronomical searching, he found Sol.

With hundreds of ships, each larger than whole Terrestrial spaceports, and traveling faster than the speed of light, the Mirans set out to move in to Solar regions and take over.

And on Earth there was nothing which would be capable of beating off this incredible armada—until Buck Kendall stumbled upon THE ULTIMATE WEAPON.

JOHN W. CAMPBELL first started writing in 1930 when his first short story, When the Atoms Failed, was accepted by a science-fiction magazine. At that time he was twenty years old and still a student at college. As the title of the story indicates, he was even at that time occupied with the significance of atomic energy and nuclear physics.

For the next seven years, Campbell, bolstered by a scientific background that ran from childhood experiments, to study at Duke University and the Massachusetts Institute of Technology, wrote and sold science-fiction, achieving for himself an enviable reputation in the field.

In 1937 he became the editor of Astounding Stories magazine and applied himself at once to the task of bettering the magazine and the field of s-f writing in general. His influence on science-fiction since then has been great. Today he still remains as the editor of that magazine's evolved and redesigned successor, Analog.